ဓရီုကျာ:ဝေါဟာရ ပထဝဳ
မုက်လိက် "ဓရီုကျာ:ဝေါဟာရ ပထဝဳ" ဝွံ ဒှ်မုက်လိက်ကမၠောန် သွက် အေန်သတဳကျုတ်ဘာသာမန် ဂွံချပ်ဂၞန်၊ ကဵုကသပ် ရေင်သကအ် ဗီုလဵု သ္ဂောအ်ကော်စ နကဵုဘာသာမန်ရ။
ဝေါဟာရ နကဵုဘာသာအင်္ဂလိက်တအ်ဂှ် ယဝ်ရ မၞးတီ ဗီုလဵု မကော်စ ဗီုမန်မ္ဂး ချူစုတ် ဗွဲသၟဝ် မဝေါဟာရဂှ်ညိ။ သာ်ဂှ်ဟွံသေင် ယဝ်ရ မၞးစှ်ေစိုတ် မအရေဝ်ဝွံ နကဵုဘာသာမန် ကော်ဗီုဏအ်မ္ဂး ကိတ်ညဳ ကုအခိုက်မန်မ္ဂးလေဝ် အတိုင်ကသပ်မၞးဂှ် ချူစုတ် ဗွဲသၟဝ်ဝွံညိ။ ကသပ်မၞး မကဵုတအ်ဂှ် ဒှ်ဂုဏ်ဖိုလ် ကုကမၠောန်ဝွံ ဗွဲမဇၞော်ကဵု ဒြဟတ်တုဲ ပိုယ်တင်ဂုန် လတူမၞးရ။
ကိုပ်ကၠာအိုတ်
- ဍဵုဒၞာဲ ပလေဝ်ဒါန် တမ်ကၞက် (နွံလတူ လပါ်တဲပါဲ)
- ဒၞာဲဇကုမချူဂှ် ဗွဲကိုပ်ကၠာအိုတ် စုတ် (:) (ကမ္မာ အင်္ဂလိက်) တုဲ
- ချူလညာတ်ဇကုညိ။
- လက္ကရဴအိုတ် ထ္ပက်ကဵု စၟတ်တဲ နကဵု မဍဵု ဗွဲလတူ လပါ်တဲပါဲ လတူသင်္ကေတ စၟတ်တဲ (နွံလတူ လပါ်တဲပုင်) ဂှ်ညိ။ သာ်ဂှ်ဟွံသေင် ချူ ~~~ ပိတဲညိ။
- absolute location
- The particular location of a point on the Earth's surface that can be expressed by a grid reference such as latitude and longitude. (ဒၞာဲဒတန် လတူဗလးမုက်ဂၠးတိ မစၞောန်ထ္ၜး နကဵုမဒုင်သဇိုင် နိဿဲ ကုခံက်အင် latitude ကဵု longitude။
- ဒတန်ဨကန် (ဝါ) ဒတန်ပကတိ--Naisikechan (ဓရီု) ၂၀:၄၈၊ ၁၅ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- အဲဒးဂၞပ် ကသပ် သိုက်ဆာန် မကဵုလဝ်လညာတ် absolute နဒဒှ် ဨကန်၊ တုဲ location နဒဒှ် ဒတန်။ ရံင်ကဵုအရေဝ်မန် မဟီုဂး တသိုက်ဨကန် (ဂွံဓဝ်အရဟတ္တမဂ် အရဟတ္တဖဵု မတွံဂးနိဗ္ဗာန်တုဲ ဒှ်တသိုက်ဨကန္တရ (အဘိဓာန်နာဲသက်လောန် ၁၀၄) တုဲ ဒတန်ဨကန် ဟီုဂှ် ဂပ်ဝ်ကွေဟ်ရ။--Htawmonzel (ဓရီု) ၁၄:၅၁၊ ၁၆ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- accessibility
- A locational characteristic that permits a place to be reached by the efforts of those at other places.
- accessibility resource
- A naturally emergent landscape form that eases communication between areas.
- အစောံသတ္တိမအာစိုပ်မာန်--Naisikechan (ဓရီု) ၂၀:၅၁၊ ၁၅ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- ဒဵုပၟတ်ဒမျိုၚ် Naisikechan (ဓရီု)
- ဒမျိုင် ဂှ် မဂွံအဓိပ္ပါယ် အသာ်လမ္စံက် မွဲဂကူ၊ ဥပမာ ဇြုံဇာတ်ဒမျိုင်။ စၞးဂှ် ဂမျိုင် မ္ဂး ဒးဂၠိုင်ရ။ ဂမျိုင် ဂှ် ဒှ်မနာမ် မကၠုင် နူကြိယာ ဂျိုင်။--Htawmonzel (ဓရီု) ၁၈:၁၃၊ ၁၅ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- လ္ဂောဝ် ဝါ တဲကြုၚ် ဝါ ကောန်ကြုၚ်--Naisikechan (ဓရီု) ၂၀:၅၁၊ ၁၅ အဝ်ဂေတ် ၂၀၂၀ (+0630)}}
- ပထဝဳပရေၚ်တဵုလွဳ--Naisikechan (ဓရီု) ၂၀:၅၅၊ ၁၅ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- ဒၞာဲဏအ် ဆက်စပ်ဒၟံင် မအရေဝ် agriculture ရ။ agriculture ဂှ် ရဲနဲကဲဗၟာမဖန်ဗဒှ် အရေဝ်ဗၟာ မွေးမြူရေး တုဲ ပိုယ်ကၠာဲ ပရေင်တဵုလွဳ ဂှ် ဂပ်ဝ်ညိဟာ။ "တဵု" ကီု "လွဳ"ကီု ဒှ်မကြိယာသီုၜါ။ ရံင်ကဵု အခိုက်အရေဝ်မန်မ္ဂး ဥပမာ ဗ္ၚ (ဝါ) ကမၠောန်ဗ္ၚ ဂှ် မုဟိုတ်မန်ပိုယ် တမၠာတေအ် ညးဟွံဟီု ကမၠောန်တဵုသြောအ်ရော။ စၞးဂှ် ညးဗဒှ်လဝ် အရေဝ်တၞဟ်ခြာ ဗ္ၚ၊ ဗ္ၚ ဂှ် ဂွံဆဵုကေတ်ဒၟံင် နူကဵု မန်တြေံ (အေဒဳ ၁၁ ဗွဝ်ကၠံ) ညးချူ "ဗ္ငအ်" (ဂစိုတ်အ် ရမ္သာင်ဟွံတိတ်၊ ညးဗှ် ဗ္ၚ)။ ဗ္ၚအရေဝ်မန် နူတမၠာတေအ်ဂှ် ဂွံအဓိပ္ပါယ် အရာမတဵုလွဳ သီုဖအိုတ်ဒှ်မာန်။ ပ္ဍဲဒၞာဲဏအ် ယဝ်ရ စကာ "တိဗ္ၚ" ဗွဲဓမ္မတာမ္ဂးရော၊ ဟွံခိုဟ်ဟာ။--Htawmonzel (ဓရီု) ၁၅:၁၄၊ ၁၆ အဝ်ဂေတ် ၂၀၂၀ (+0630)
{{defn|Characteristic of or resembling the European Alps, or any other high-elevation mountain range or mountainous environment (especially one deeply modified by glacial erosion so as to contain characteristic landforms such as cirques, horns, etc.), in topography, climate, or ecological communities.
- ကဝေက် (မနာမ်) ကဝေက်မကလောံကလေန်နူကဵုဍာ်ကြေက်ဒဵုပၟတ် (ဝါ) အရာမပရာတ်တိတ်ကၠုၚ်ဟိုတ်နူဒဵုပၟတ်ခတိုဟ် --Monbeeree (ဓရီု) ၁၇:၂၂၊ ၁၇ အဝ်ဂေတ် ၂၀၂၀ (+0630)
ကကကိကိ Htawmonzel (ဓရီု) ၁၈:၀၆၊ ၁၆ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- backslope
- The part of the profile of a hillslope that forms the steepest, typically linear portion of the slope, generally located in the middle and bounded by a convex shoulder above and a concave footslope below. The backslope may or may not include vertical or near-vertical cliffs.
- backwater
- A part of a river in which there is little or no current.
- badlands
- An area of rugged or irregular topography resulting from extensive wind and water erosion of sedimentary rock.
- bajada
- A series of adjacent alluvial fans coalescing in a basin at the foot of a mountain range.
- bar
- An elevated region of sediment such as sand or gravel which has been deposited by the flow of a river or other moving body of water. See also shoal.
- barrier ridge
- Any steep, unnavigable ridge or escarpment isolating one terrain from another.
- base level
- The lowest level to which a stream can erode its bed. The ultimate base level of all streams is the sea.
- basin
- See depression.
- batholith
- A very large body of igneous rock, usually granite, which has been exposed by erosion of the overlying rock.
- bathymetry
- 1. The measurement of water depth, mainly of seas and oceans but sometimes of deep lakes.
- 2. The study and depiction of the physical features or relief of the floor of a lake or ocean. In this sense bathymetry is considered the underwater equivalent of hypsometry or topography.
- bay
- A coastal body of water that is directly connected to but recessed from a larger body of water, such as an ocean, sea, lake, or another bay. The land surrounding a bay usually shelters it from strong winds and waves, making bays ideal places for ports and harbors.
- beach
- A landform along the shoreline of an ocean, sea, lake, or river with a loose surface of sand, gravel, shingle, pebbles, shells, stones, or coral.
- bearing
- The direction or position of an object, or the direction of an object's movement, relative to a fixed point. It is typically measured in degrees and can be determined with a compass. By convention, magnetic north is defined as having a bearing of zero degrees.
- bedrock
- The solid rock in the Earth's crust that underlies all soil and other loose material; the rock material that breaks down eventually to form soil.
- berm
- 1. A level space, shelf, or raised barrier separating two areas, often man-made and built of compacted earth. Berms often function as impoundments, fortification lines, or border walls and other lines of demarcation.
- 2. A low, impermanent, nearly horizontal or landward-sloping shelf, ledge, or narrow terrace on the backshore of a beach and parallel to the shoreline, formed by waves which deposit material beyond the average high water line, e.g. during storms. Some beaches have no berms; others may have one or more.
- bight
- A bend or curve in a coastline, river, or other geographical feature typically indicating an especially large, open bay that is shallower than a sound.
- biological diversity
- A concept recognizing the variety of life forms in an area of the Earth and the ecological interdependence of these life forms.
- biogeography
- The study of the distribution of biological species and ecosystems in geographic space and through geological time.
- biosphere
- The realm of all living things.
- biota
- The animal and plant life of a region considered as a total ecological entity.
- blowout
- A sandy depression formed when wind erodes into patches of bare sand on otherwise vegetation-stabilized sand dunes at the margins of coastal and arid ecosystems.
- bocage
- A landscape of mixed woodland and pasture, with fields and winding country lanes sunken between low, narrow ridges and banks surmounted by tall, thick hedgerows, especially as found in rural parts of western Europe.
- body of water
- Any significant accumulation of water, either natural or artificial, on the surface of the Earth. Bodies of water may hold or contain water, as with lakes and oceans, or they may collect and move water from one place to another, as with rivers, streams, and other watercourses.
- bog
- A type of wetland which accumulates deposits of dead plant material, especially mosses, known as peat. Bogs occur where the water at the ground surface is acidic and low in dissolved nutrients. They are one of four main types of wetland.
- bootheel
- See salient.
- border
- The geographical boundary of a political entity or legal jurisdiction, such as a country, state, or other subnational entity.
- bornhardt
- A bald, steep-sided, dome-shaped hill, mountain, or rock outcropping at least 30 မဳတာs (98 ft) in height and several hundred meters in width. Compare inselberg, tor, and nubbin.
- borough
- A type of administrative subdivision in certain English-speaking parts of the world. Though traditionally used to refer to a fortress or a walled town, modern usage of the term can variably refer to any town with its own local self-government, a formal or informal subdivision of a large metropolis (as in New York City and London), or an entire administrative region (as in the U.S. state of Alaska).
- box canyon
- A short, narrow canyon with steep walls on three sides, allowing entry and exit only through the mouth of the canyon.
- break-in-bulk point
- A transfer point on a transport route where the mode of transport or type of carrier changes and where large-volume shipments are reduced in size. For example, goods may be unloaded from a ship and transferred to trucks at an ocean port.
- breakwater
- Any man-made structure built on the coast of a body of water, typically the sea, in order to reduce the intensity of wave action in an area adjacent to the shore, thereby providing safe harbourage for human activities in the inshore waters. Breakwaters may also be designed to protect the coastline from coastal erosion and longshore drift.
- built environment
- The human-made spaces that provide the setting for human activity, in which people live, work, and recreate on a day-to-day basis.
- butte
- An isolated hill or mountain with steep or precipitous sides, usually having a smaller summit area than a mesa.
- cadastre
- A type of parcel-based land recording system containing a comprehensive record of interests in individual units of land within a country or other polity, usually including a geometric description of each parcel's physical location, dimensions, and boundaries that is linked to legal information detailing the nature of the interests (e.g. rights, restrictions, and responsibilities), the ownership or control of those interests, and the economic value of the land and its improvements. The cadastre is a fundamental source of data used in resolving disputes between landowners.
- calanque
- A narrow, steep-sided valley surrounding an inlet formed in karstic regions along the Mediterranean coast, either by fluvial erosion or the collapse of the roof of a cave that has been subsequently partially submerged by a rise in sea level.
- caldera
- A large, cauldron-shaped depression that forms through the subsidence and collapse of a ground surface following the evacuation of an underlying magma chamber.
- canal
- A navigable artificial water channel, usually built as a conduit for human activity.
- canyon
- A deep cleft between cliffs or escarpments, or a rift between two mountain peaks, resulting from weathering and the erosive activity of a river over long periods of geologic time.
- cape
- A large headland or promontory extending into a body of water, usually a sea or ocean.
- caprock
- A stratum of erosion-resistant sedimentary rock (usually limestone) found in arid areas. Caprock forms the top layer of most mesas and buttes.
- cardinal directions
- The set of four primary directions used in cartography and navigation: north (N), south (S), east (E), and west (W). Together they form the primary divisions of the compass rose. They can be further subdivided into the intercardinal directions and secondary-intercardinal directions.
- carrying capacity
- The total number of human beings that an area can support given the quality of the natural environment and the level of technology of the population.
- cartography
- The study and practice of making maps and charts. A person who draws or makes maps or charts is called a cartographer.
- cartogram
- A map in which some thematic mapping variable, such as travel time, population, or gross national product, is substituted for traditional measures of land area or distance such that the geometry or space of the map is distorted in order to convey and emphasize the information of the alternate variable.
- cave
- Any naturally hollow underground space large enough for a person to enter.
- cavern
- A type of solutional cave that is formed in soluble rock with the ability to grow speleothems.
- cay
- A small, sandy, low-elevation island on the surface of an otherwise submerged coral reef; a type of coral island. Compare atoll.
- celestial pole
- Either of the two imaginary points in the sky at which an indefinitely extended projection of the Earth's axis of rotation intersects the celestial sphere. As the Earth rotates upon its axis, the north and south celestial poles remain permanently fixed in the sky (directly overhead to observers at the North Pole and South Pole, respectively), and all other points appear to rotate around them.
- cenote
- A natural pit or sinkhole resulting from the collapse of limestone bedrock which exposes groundwater underneath.
- central business district
- A centrally located commercial business district in an urban area, typically containing a concentration of office and retail activities.
- census-designated place (CDP)
- A concentration of population identified by the United States Census Bureau for statistical purposes.
- chain {{defn|A unit of length equal to 66 ပေs (20.117 m), used especially in public land surveys in the United States; 10 square chains is equal to 1 ဨက (0.40 ဟက်တာs). Though the literal chains used to measure this distance have long been superseded, surveying tapes are often still called "chains", and measuring with a tape may be called "chaining".
- channel
- 1. A waterway separating two relatively close landmasses.
- 2. Any narrow body of water that connects two larger bodies of water.
- 3. The deepest part of a shallow body of water, often used as a passageway for large ships.
- chaparral
- A class of terrestrial vegetation characterized by dense, impenetrable thickets of shrubs or dwarf trees.
- chart {{defn|A special-purpose map designed for navigation, especially nautical and aeronautical navigation, or to present specific data or technical information.
- chimney
- See salient.
- chine
- A steep-sided coastal gorge, typically of soft eroding cliffs of sandstone or clay, through which a river or stream flows to the sea. The term is used primarily in southern England.
- chinook
- A warm, dry wind experienced along the eastern side of the Rocky Mountains in the United States and Canada. Most common in winter and spring, it can result in a rise in temperature of 20 °C (68 °F) in a quarter of an hour.
- chorography
- The art of establishing, describing, or mapping a geographic region or district, or more broadly, the representation of space or place.
- choropleth {{defn|A map showing the distribution of a phenomenon by graded shading which indicates the density per unit area of that phenomenon; the darker the shading, the greater the density.
- cinder cone
- A steep-sided volcano formed by the explosive eruption of cinders that form around a vent. Cinders are lava fragments about 1 centiမဳတာ (0.39 in) in diameter.
- circle of latitude
- See latitude.
- cirque
- An amphitheatre-shaped valley surrounded on three or more sides by steep, cliff-like slopes and formed by glacial or fluvial erosion.
- city
- A large human settlement, generally with extensive systems constructed for housing, transportation, sanitation, utilities, and communication.
- city-state
- A sovereign state or small independent country that usually consists of a single city and its dependent territories.
- cliff
- Any vertical or nearly vertical rock exposure, usually formed by the processes of weathering and erosion.
- climax vegetation
- The vegetation that would exist in an area if growth had proceeded undisturbed for an extended period. This would be the "final" collection of plant types that presumably would remain forever, or until the stable conditions were somehow disturbed.
- coast
- The area where land meets a sea or ocean. Coastal zones are regions where the interaction of terrestrial and marine processes occurs. Compare shore.
- col
- The lowest point on a mountain ridge between two peaks.
- colony
- A territory under the immediate complete political control of a sovereign metropolitan state but otherwise distinct, often geographically, from the state's home territory. Colonies have no international representation independent of the metropolitan state. Compare satellite state.
- commonwealth
- compass
- An instrument used for navigation and orientation that indicates direction relative to the geographic cardinal directions by measuring the orientation of the Earth's magnetic field with respect to the North Magnetic Pole. Compasses often display markings for angles or degrees, which allow them to show azimuths and bearings, in addition to a compass rose.
- compass rose
- A figure on a compass, map, nautical chart, or monument used to display the orientation of the four cardinal directions — North, East, South, and West — and their intermediate points.
- confluence
- The place at which two or more rivers or other watercourses flow together to form one larger river or watercourse.
- coniferous
- Bearing cones; from the conifer family.
- contiguity
- The characteristic of a group of neighboring political or geographical divisions not being interrupted by politically unaffiliated land or water. Such divisions are said to be contiguous.
- continent
- One of several very large, contiguous landmasses into which the Earth's land area is divided, generally by geographical or political convention rather than any strict criteria. Geologically, continents correspond largely to areas of continental crust on continental plates.
- continental climate
- The type of climate found in the interior of the major continents in the middle, or temperate, latitudes. The climate is characterized by a great seasonal variation in temperatures, four distinct seasons, and a relatively small annual precipitation.
- continental divide
- The line of high ground that separates the different oceanic drainage basins of a particular continent. The river systems of a continent on opposite sides of a continental divide flow toward different oceans. See drainage divide.
- continental shelf
- A portion of a continent that is submerged beneath an area of relatively shallow water known as a shelf sea. Though continental shelves are usually treated as physiographic provinces of the ocean, they are not part of the deep ocean basin proper but the flooded margins of the continent.
- continentality
- The quality of being located on a continent.
- contour line
- A line marked on a topographic map which connects points of equal elevation above or below a specified reference datum. Multiple contour lines, each representing a different elevation, are depicted together to show the shape of the terrain within the map area.
- contour interval {{defn|The difference in elevation between any two adjacent contour lines as depicted on a particular topographic map.
- conurbation
- An extensive urban area formed when two or more initially separate cities coalesce to form a continuous metropolitan area.
- core area
- The portion of a country that contains its economic, political, intellectual, and cultural focus. It is often the center of creativity and change. See hearth.
- corrasion
- The process of mechanical erosion of the Earth's surface by the impact or grinding action of particles being transported across it, either by moving water, waves, glaciers, wind, or gravity.
- corrie loch
- See tarn.
- coulee
- A dry canyon eroded by Pleistocene floods that cut into the lava beds of the Columbia Plateau in the western United States.
- couloir
- A narrow gully with a steep gradient in a mountainous terrain, often enclosed by sheer cliffs and filled with snow or ice even during the summer months.
- country
- A region identified as a distinct national entity in political geography. Compare state.
- county
- A type of subnational division of a country or federal state used for administrative or other purposes.
- course
- cove
- 1. A walled, rounded, cirque-like opening at the head of a small valley.
- 2. A small, narrow, sheltered bay, inlet, tidal creek, or recess in an estuary, often within a larger embayment.
- 3. A small, often approximately circular, wave-cut indentation or recess in a cliff on a large body of water, especially one with a relatively narrow or secluded entrance.
- 4. A shallow tidal river, or the backwater near the mouth of a tidal river.
- crater
- Any large, roughly circular depression, pit, or hole in the Earth's surface. Craters can be classified into different types based on their ultimate causes; see impact crater, volcanic crater, and pit crater.
- crater lake
- A lake that forms in a volcanic crater or caldera (such as a maar), an impact crater left by a meteorite, or a crater resulting from a man-made explosion.
- creek {{defn|A small, intermittent stream that is larger than a brook but smaller than a river. The term is used primarily in the United States, Canada, and Australia.
- crust
- The thin shell of solid material that is the Earth's outermost layer and the outermost component of the lithosphere. The Earth's crust is generally divided into two distinct types, oceanic crust and continental crust, both of which "float" on top of the mantle.
- cryosphere
- The totality of water in the solid phase on the Earth's surface, including glaciers; sea, lake, and river ice; snow; and permafrost. The cryosphere is sometimes considered a subset of the hydrosphere.
- cryoturbation
- The mixing of materials from various horizons of the soil down to the bedrock due to freezing and thawing.
- cuesta
- A long, low ridge with a steep scarp slope and a gentle backslope (dip slope).
- cultural geography
- A branch of human geography which studies the patterns and interactions of human culture in relation to the natural environment and the human organization of space.
- culture
- The accumulated habits, attitudes, and beliefs of a group of people that define for them their general behavior and way of life; the total set of learned activities of a people.
- culture hearth
- The area from which the culture of a group diffused. See hearth.
- cut bank
- A continually eroding bank along a meandering river or stream channel, especially a bank that has been eroded into a nearly vertical cliff. Cut banks generally form on the outside bend of a deep meander, opposite the depositional point bar that forms on the inside bend.
- cutoff {{defn|The new channel formed when a meandering stream erodes through a narrow strip of land and thereby shortens the length of the main channel.
- cwm
- See cirque.
- Cyclopean stairs
- A term referring to the longitudinal profile of some glaciated valleys which have been eroded into a series of consecutive hanging valleys resembling stairs.
- dale
- Another name for a valley.
- dam
- Any barrier, either natural or artificial, that stops or restricts the flow of water, either on the surface or underground. Man-made dams are most commonly built to impound rivers or streams, generally to retain water for purposes such as human consumption, irrigation, aquaculture, or power generation (whereas related structures such as floodgates and levees are more specifically designed to manage or prevent water flow into particular areas).
- de facto segregation
- The spatial and social separation of populations that occurs without legal sanction.
- de jure segregation
- The spatial and social separation of populations that occurs because of legal measures.
- debouch
- A place where water runoff from a relatively small, confined space emerges into a much larger, broader space, or where a body of water pours forth from a narrow opening, such as where a stream or river enters a lake or ocean.
- deciduous forest
- A forest composed of trees which lose their leaves each year.
- defile
- A narrow pass or gorge between mountains or hills.
- degree
- A unit of angular measure. A circle is divided into 360 degrees, represented by the º symbol. Degrees are used to divide the roughly spherical shape of the Earth for geographic and cartographic purposes.
- degree day
- Deviation of one-degree temperature for one day from an arbitrary standard, usually the long-term average temperature for a place.
- dell
- A small, secluded hollow, usually within a grassy, park-like, partially wooded valley.
- delta
- A landform at the mouth of a river where the main stem splits up into several distributaries. It is formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river. Compare estuary.
- demography
- The systematic analysis of population.
- depression
- Any landform that is sunken or depressed below the surrounding area. Depressions include an enormous variety of landforms and can form by a number of different mechanisms, including erosion, ground collapse, tectonic activity, volcanism, and meteorite impacts.
- desert
- An arid, barren area of land where little precipitation occurs and living conditions are consequently unfavorable for most plant and animal life. Deserts are characterized by exposure of the unprotected ground surface to processes of denudation as well as large variations in temperature between night and day. They are often classified by the amount of precipitation they receive, by their average temperature, by the causes of their desertification, or by their geographical location.
- digital elevation model (DEM)
- A three-dimensional computer graphics representation of a geographic terrain surface created from elevation data. DEMs are the most common basis for digitally produced relief maps.
- dike
- See levee.
- dissected plateau
- A landscape produced by significant stream erosion and incision of a plateau such that only a small part of the plateau surface is at or near the original level of the summit; much of the area instead occurs as eroded hills or badlands.
- distance decay
- The decrease in cultural or spatial interactions between two places as the distance between them increases. This effect may be noticeable in towns and cities, where certain descriptive characteristics such as pedestrian traffic, building height, and land value tend to decline with greater distance from the city center.
- distributary
- A stream or river that branches off and flows away from a main channel. Distributaries are common near river deltas. Contrast tributary.
- district
- dome
- 1. A steep-sided mound that forms when very viscous lava is extruded from a volcanic vent.
- 2. An uplifted area of sedimentary rock with a downward dip in all directions, often caused by molten rock material pushing upward from below. The sediments have often eroded away, exposing the rocks that resulted when the molten material cooled.
- dormant volcano
- An active volcano that is in repose (quiescence) but is expected to erupt in the future.
- drift ice
- A type of sea ice consisting of multiple ice floes that are not attached to the shoreline or any other fixed object such as a shoal, and which are therefore free to "drift" under the influence of winds and ocean currents. Contrast fast ice.
- drainage basin
- Any area of land where precipitation collects and drains into a common outlet, such as a river, lake, ocean, or any other body of water. The drainage basin includes all of the surface water from precipitation runoff and snowmelt, as well as all of the groundwater beneath the Earth's surface. Each drainage basin is separated topographically from adjacent basins by a drainage divide.
- drainage divide
- The topographical barrier that separates neighboring drainage basins. Divides are often, though not always, located along conspicuous elevated ridges or mountain ranges.
- draw
- 1. A terrain feature formed by two parallel ridges or spurs with low ground in between them.
- 2. Another name for an arroyo, ravine, or gulch, especially one with a broad floor and gently sloping sides.
- drumlin
- An elongated hill in the shape of an inverted spoon or half-buried egg which is formed by glacial ice acting on underlying unconsolidated till or ground moraine.
- dry farming
- A type of farming practiced in semi-arid or dry grassland areas without irrigation using such approaches as fallowing, maintaining a finely broken surface, and growing drought-tolerant crops.
- dry point
- An area of firm or dry ground in a wetland, marsh, or floodplain, often capable of supporting a human settlement.
- dune
- A hill of loose sand built by the movements and erosional and depositional processes of wind or water, often occurring in deserts and coastal areas.
- Earth science
- 1. A collective term for the various fields of natural science related to the planet Earth.
- 2. The branch of science that studies the physical constitution and characteristics of the Earth and its atmosphere, using methods and tools from geography, geology, physics, chemistry, biology, and mathematics to build a quantitative understanding of how the Earth works and changes over time.
- earthquake
- The sudden and intense shaking of the ground due to tectonic activity.
- Eastern Hemisphere
- The half sphere of the Earth that is east of the Prime Meridian and west of the antimeridian. It is opposite the Western Hemisphere.
- easting
- economic geography
- A sub-discipline of geography which studies the location, distribution, and spatial organization of economic activities across the world.
- economies of agglomeration
- The economic advantages that accrue to an activity by locating close to other activities; benefits that follow from complementarity or shared public services.
- ecoregion
- A type of biogeographic province that is smaller than a bioregion and which contains characteristic, ecologically and geographically distinct, and relatively uniform assemblages of biological communities and species. Ecoregion boundaries often overlap within ecotones and mosaic habitats, and most ecoregions contain habitats that differ from those described for their assigned biome.
- edge city
- A concentration of businesses, commercial buildings, or retail and entertainment venues situated outside of a traditional downtown or central business district in what was previously a suburban residential or rural area.
- edgelands
- The transitional areas of "fringe" space at the boundaries of a country, city, or other artificial geographical entity, often distinguished by a partly man-made, partly natural landscape that is in the earliest stages of human management and organization. Compare hinterland.
- ekistics
- The scientific study of human settlements of all types, incorporating concepts such as regional, metropolitan, and community planning and dwelling design with the goal of achieving harmony between the inhabitants of a settlement and their physical, social, and cultural environments.
- elevation
- The height of a point on the Earth's surface with respect to sea level. Compare altitude.
- emergent coastline
- A coast or shoreline resulting from a rise in land surface elevation relative to sea level.
- enclave
- A tract or territory completely surrounded by and enclosed within the territory of one other state, country, or other political entity. Unlike enclaves, exclaves can be surrounded by more than one other state.
- endorheic basin
- A closed drainage basin that allows little or no outflow to external bodies of water but converges instead into internal lakes or swamps which equilibrate through evaporation.
- epicenter
- The point on the Earth's surface directly above the focus of an earthquake, near which the seismic waves produced by the earthquake are usually most noticeable.
- Equator
- The imaginary circle around the Earth halfway between the geographic poles which is assigned a latitude of zero degrees and is therefore used as a reference point for all other lines of latitude. It is the largest circumference of the Earth.
- erratic
- A boulder that has been carried from its source by a glacier and deposited as the glacier melted. Such boulders are often of different rock types than the surrounding rocks.
- escarpment
- A long cliff or steep slope separating two comparatively level or more gently sloping surfaces and resulting from erosion or faulting.
- esker
- A long, winding ridge of stratified sand and gravel, usually occurring in glaciated or formerly glaciated areas.
- estuary
- The broad lower course of a river where it enters the ocean and is affected by the tides. Compare delta.
- etchplain
- A plain beneath which the bedrock has been subjected to considerable subsurface weathering, known as "etching". Erosion of the regolith overlying an etchplain often exposes topographical irregularities such as inselbergs.
- evapotranspiration
- The process by which water is lost from an area through the combined effects of evaporation from the ground surface and transpiration from vegetation.
- evorsion
- See pothole.
- exclave
- A portion of a state or territory that is geographically separated from the main part by surrounding foreign territory of one or more other states or political entities. Many exclaves are also enclaves.
- exotic stream
- A stream found in an area that is too dry to have spawned such a flow. The flow originates in some moister section.
- extinct volcano
- A volcano that is not expected to erupt again.
- exurban
- An adjective describing a region or district that lies outside a city and usually beyond its suburbs; a place of this type is called an exurb. Compare rural.
- fall line
- A geomorphologic unconformity between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock.
- fallow
- Agricultural land that is plowed or tilled but left unseeded during a growing season. Fallowing is usually done to conserve moisture and soil nutrients.
- fast ice
- fault
- A fracture in the Earth's crust accompanied by a displacement of one side of the fracture.
- fault-block mountain
- A mountain mass created by either the uplift of land between faults or the subsidence of land outside the faults.
- fault zone
- An area of numerous fractures in the Earth's crust along which movement has occurred. The movement may be in any direction and involve material on either or both sides of the fractures.
- federation
- A form of government in which powers and functions are divided between a central government and a number of political subdivisions that have a significant degree of political autonomy.
- fen
- field
- A quantity or observation, such as temperature, soil moisture, or population density, that can be theoretically assigned to any point of space. Both scalar and vector fields are found in GIS applications, although the former is more common.
- figure of the Earth
- The size and shape of the Earth as studied in geodesy. Applications requiring varying levels of precision have led to the development of many different models of the Earth, ranging from simple spheres to much more accurate approximations such as geoids.
- firn
- A type of ice that is at an intermediate stage between snow and glacial ice. More specifically, firn is partially compacted névé left over from past seasons which has subsequently recrystallized into a form that is harder and denser than névé.
- firth
- Another name for a coastal inlet, strait, or bay associated with the mouth of a large river, where the tidal effects of seawater passing upriver have widened the riverbed into an estuary. The term is used primarily in Scotland.
- fish ladder
- A series of shallow steps down which water is allowed to flow, designed to permit salmon or other anadromous fish to circumvent artificial barriers such as dams as they swim upstream to spawn.
- fissure
- A long, narrow opening or line of breakage made by cracking or splitting, especially in rock or earth.
- fjord
- A long, narrow marine inlet with steep sides or cliffs created by glacial erosion.
- floodplain
- A broad, flat area of land adjacent to a river or stream which is leveled by annual flooding and by the lateral and downstream movement of meanders.
- fluvial
- Of or pertaining to rivers or streams; produced by the action of a river or stream.
- focality
- The characteristic of a place that follows from its interconnections with more than one other place. When interaction within a region comes together at a single place (i.e. when the movement focuses on that location), the place is said to possess focality.
- focus
- The point inside the Earth's crust from which an earthquake originates.
- foothills
- A geographic transition zone defined by gradual increases in elevation between plains or low-relief hills and adjacent topographically higher hills, mountains, or uplands.
- footslope
- The part of the profile of a hillslope that forms the concave surface at the base of the slope. It is a transition area between sites of erosion and transport higher up the slope (e.g. the shoulder and backslope) and sites of deposition further down the slope (the toeslope).
- forest
- Any extensive area dominated by communities of trees.
- fresh water
- Any naturally occurring water characterized by low concentrations (typically less than 0.05% by volume) of dissolved salts and other solids relative to either salt water or brackish water. Sources of fresh water on Earth include glaciers, ice caps, icebergs, bogs, lakes, rivers, streams, and most groundwater.
- functional diversity
- The characteristic of a place where a variety of different activities (economic, political, or social) occur, most often associated with urban places.
- gazetteer
- A geographical dictionary or directory used in conjunction with a map or atlas and containing information concerning the geographical make-up, social statistics, and physical features of a country, region, or continent.
- geodesic
- geodesy
- The science of accurately measuring and understanding the Earth's geometric shape, orientation in space, and gravitational field and how these properties change over time.
- geodetic control network
- geodetic datum
- A coordinate system and set of reference points used for locating places on the Earth, which defines horizontal and vertical coordinates upon a particular reference ellipsoid that approximates the figure of the Earth. Geodetic datums are used in geodesy, navigation, and surveying applications to translate positions indicated on paper or digital maps to their actual positions on the Earth; because the Earth is an imperfect ellipsoid, localized datums such as the ED50 covering only specific countries or regions are often more accurate representations of their area of coverage than global standards such as the WGS 84 of the World Geodetic System.
- geodynamics
- A subfield of geophysics and Earth science that studies the physical dynamics of the Earth by applying physics, chemistry, and mathematics to the understanding of how mantle convection and other internal processes lead to plate tectonics and geological phenomena such as mountain formation, volcanism, earthquakes, and faulting, among others.
- geographic coordinate system
- A coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters, or symbols. Geographic coordinates are often chosen such that one of the numbers represents a vertical position such as elevation and two or three other numbers represent a horizontal position such as latitude and longitude.
- geographic information science (GIS)
- The scientific study of data structures and computational techniques for capturing, representing, processing, and analyzing geographic information.
- geographic information system (GIS)
- Any system of computer software tools designed to allow users to record, store, manipulate, analyze, manage, and present large sets of spatial or geographic data.
- Geographic Names Information System (GNIS)
- A digital public-domain database developed by the U.S. Geological Survey and the U.S. Board on Geographic Names which contains name and locative information about more than two million physical and cultural features located throughout the United States and its territories. Each feature recorded in the database receives a unique feature record identifier called a GNIS identifier.
- geographical mile
- A unit of length defined as the distance equal to one minute of arc along the Earth's Equator: approximately 1,855.3 မဳတာs (1.1528 mi; 1.8553 km). The precise length varies with the reference ellipsoid used to approximate the shape of the Earth. Regardless of the particular ellipsoid, the length of one degree of longitude at the Equator is equal to exactly 60 geographical miles.
- geography
- The scientific study of the lands, features, inhabitants, and phenomena of Earth.
- geoid
- The shape that the surface of the Earth's oceans would take under the influence of Earth's gravity and rotational acceleration alone, in the absence of other influences such as winds and tides. It is often characterized as the precise mathematical figure of the Earth: a smooth but irregular gravitational equipotential surface at every point of which, by definition, the direction of the force of gravity is always perpendicular and spirit levels are always parallel. Its shape results from anomalies in the Earth's gravitational field caused by the uneven distribution of mass within and on the Earth's surface. A reference ellipsoid is an idealized approximation of the more complex and accurate geoid.
- geoinformatics
- The science and technology which develops and uses information science infrastructures to address problems and analyze data within geography, cartography, geoscience, and related branches of science and engineering.
- geolocation
- The identification or estimation of the real-world geographic location of an object, involving the generation of a set of geographic coordinates in order to determine a more meaningful description of location, such as a street address.
- geomatics
- The scientific discipline that involves gathering, storing, processing, and delivering geographic or spatially referenced information.
- geomorphology
- The study of the arrangement and form of the Earth's crust and of the relationship between these physical features and the geologic structures beneath.
- geoscience
- See Earth science.
- geosphere
- The collective non-living parts of the Earth: the lithosphere, the atmosphere, the cryosphere, and the hydrosphere.
- geostatistics
- A branch of statistics which involves the organization, management, and analysis of spatial and spatiotemporal datasets. Geostatistical algorithms are often incorporated in GIS software applications.
- ghetto
- A section of a city occupied by members of a minority group who live there because of social restrictions on their residential choices. Originally, the term referred specifically to a section of a European city to which Jews were confined.
- glacial till
- The mass of rocks and finely ground material carried by a glacier and deposited when the ice melts. This creates an unstratified material of varying composition.
- glaciation
- 1. The process or state of being covered with a glacier.
- 2. Another name for a glacial period, an interval of time that is marked by colder temperatures and advancing glaciers.
- glacier
- A persistent mass of dense ice that is constantly moving under its own weight, and which is composed largely of compacted snow that forms where the annual accumulation of snow exceeds its melting and sublimation over very long periods of time. Glaciers slowly deform and abrade the land beneath them, creating a huge variety of landforms including cirques, moraines, and fjords. They form exclusively on land and are distinct from the much thinner ice that forms on bodies of water.
- glade
- Any large, open, mostly treeless area within a forest.
- glen
- A long valley bounded by gently sloping, concave sides, and typically narrower and deeper than a strath. The term is used primarily in Scotland.
- global city
- A city which functions as an important or primary node in the global economy. Though criteria are not strictly defined, a global city typically is very large; dominates trade and economic interactions within a large surrounding area; supports a large and demographically diverse population; serves as a center of ideas and innovation in business, science, culture, and politics; and/or is a headquarters for major financial institutions, multinational corporations, or worldwide media and communications networks.
- Global Positioning System (GPS)
- A satellite-based radionavigation positioning system owned and operated by the United States Department of Defense and made available for use by both the military and the general public. It is one of several GNSS standards that provides geolocation and time information, transmitted via microwave signals, to enabled satellite navigation devices, known as GPS receivers, anywhere on or near the Earth where there is an unobstructed line of sight to at least four GPS satellites. Modern state-of-the-art GPS receivers can accurately pinpoint locations to within 30 centiမဳတာs (0.98 ft).
- globalization
- The process of interaction and integration among people, companies, governments, and cultures across the world. A complex and multifaceted phenomenon, globalization is considered largely the result of economically motivated advances in transportation and communication technologies in the past several centuries which have dramatically increased interactions between otherwise isolated groups of people.
- globe
- A true-to-scale map of the Earth that duplicates its round shape and correctly represents relative areas, sizes, and shapes of physical features, distances, and directions.
- gnamma
- See panhole.
- gorge
- See canyon.
- graben
- A depression or valley bounded on either side by distinct, parallel escarpments or faults and formed by the downward displacement of a block of the Earth's crust. Grabens often occur side-by-side with horsts, their uplifted or non-displaced counterparts, in a repeated series of vertical displacements.
- grade
- A physical surface that is inclined with respect to the horizontal, or the angle between that surface and the horizontal, typically expressed in degrees, or calculated as a ratio of "rise" (vertical distance) to "run" (horizontal distance) and expressed as a fraction or percentage; a larger number indicates a steeper incline. The term "grade" is often used to describe the incline of man-made surfaces such as roads and the roofs of buildings, whereas the term "slope" is more commonly used to describe natural surfaces such as the sides of hills or mountains or the beds and banks of watercourses.
- graticule
- A network of lines on a map or chart (or imagined on the surface of the Earth) representing geodetic parallels of latitude and meridians of longitude.
- great circle
- Any circle on the surface of a sphere created by the intersection of the sphere and a plane that passes through its center. A great circle divides the sphere into two equal hemispheres, and all of a sphere's great circles have the same center and circumference as each other, which by definition is the largest possible circumference of the sphere. The mathematical properties of great circles make them useful in geodesy, where they are often visualized upon the surface of the Earth (despite the fact that the Earth is not a perfect sphere): for example, the Equator of the idealized Earth is a great circle, and any meridian with its antimeridian forms a great circle. Because the shortest path between any two points on the surface of a sphere follows the arc of a great circle, great-circle distances are often used as approximations of geodesics for the purposes of air and sea navigation.
- great-circle distance
- A route which follows the arc of a great circle as defined by the intersection of the Earth's surface with an imaginary plane passing through the Earth's center. It is the shortest route between two places on the Earth's surface.
- grid
- A pattern of lines on a chart or map, such as those representing latitude and longitude, which helps determine absolute location.
- grid north
- The direction northwards as indicated by the grid lines of a map projection, which may or may not be aligned with geodetic north. Grid north may also differ from magnetic north.
- groundwater
- The water present beneath the Earth's surface in soil pore spaces and in fractures and voids within geological strata. Contrast surface water.
- grove
- A small group of trees growing close together and generally surrounded by little or no undergrowth.
- growing season
- The part of the year during which local weather conditions (i.e. temperature and precipitation) permit the normal growth of plants in a given location. What defines a "growing season" is often informal and colloquial, and may vary widely by location and from year to year; in many places, the local growing season is defined as the period of time between the average date of the last frost (in temperate parts of the Northern Hemisphere, this typically occurs in the spring) to the average date of the first frost (in the autumn).
- groyne
- A rigid, man-made hydraulic structure extending from an ocean shore or river bank, constructed to interrupt water flow and limit the movement of sediment by longshore drift.
- gulch
- A deep, V-shaped valley formed by erosion, often containing a small stream or a dry streambed, especially one in arid regions.
- gulf
- A large arm or inlet of an ocean or sea that lies within a curved coastline, similar to a bay but usually larger and often with a narrower opening.
- gully
- A landform resembling a large ditch or a small ravine created by the action of swift running water eroding deeply and sharply into soil, typically on a hillside.
- guyot
- An isolated underwater seamount with a flat top that is at least 200 မဳတာs (660 ft) below the water's surface.
- hachure
- Any of a series of non-numerical lines used on a map to indicate the general orientation and steepness of topographical terrain. Such lines vary in length, thickness, and spacing, with steeper slopes indicated by shorter, heavier, and more closely spaced lines.
- hamlet
- A small human settlement, variably defined as one the size of a town, village, or parish or as a smaller subdivision of or satellite entity to a larger settlement.
- hanging valley
- A tributary valley that is higher in elevation than the main valley into which it drains, such that it appears to be "hanging" above the lower valley. Hanging valleys are commonly the result of differential glacial erosion, when adjacent areas beneath a glacier are subjected to different rates of erosion.
- harmonic tremor
- One of a series of continuous rhythmic earthquakes in the Earth's upper lithosphere that can be detected by seismographs. Harmonic tremors often precede or accompany volcanic eruptions.
- heading
- The compass direction in which the bow or nose of a moving vessel or aircraft is pointed. This is not necessarily the same direction in which the vessel is actually traveling, known as its course; any difference between heading and course is due to the motion of the medium (the air or water) through which the vessel is moving, or other aerodynamic effects such as skidding or slipping. See also bearing.
- headland
- A high coastal promontory that extends out into a body of water, often surrounded by steep cliffs. A very large headland is often called a cape.
- headwall
- A steep slope or sheer cliff face at the upper end of a valley (e.g. at the back of a cirque), or at the active face of a mine, pit, or quarry.
- hearth
- The source area of any innovation. The source area from which an idea, crop, artifact, or good is diffused to other areas.
- heartland
- 1. The central part of a region.
- 2. A part of a region considered essential to the viability and survival of the whole.
- heath
- A shrubland habitat found mainly on free-draining, infertile, acidic soils and characterized by open, low-growing, woody vegetation.
- hedgerow
- A line of closely spaced shrubs or trees, planted and trained so as to form a barrier, to mark the boundary between two neighboring areas, or to serve as a windbreak for crops in adjacent fields.
- hemisphere
- Half of the Earth, usually conceived as resulting from the division of the globe into two equal parts of either north and south or east and west.
- ကရေက်ဂၠးတိ (Northern hemisphere) မ္ဂး ကရေက်ဂၠးတိသၟဝ်ကျာ။ အရေဝ် အင်္ဂလိက်ဏအ်ဂှ် ကၠုင်နူ လေတ်တေန် hēmi- "ကဝက်" + sphaira "အရာမခဍမ်" ဗွဲကြဴ ဂွံအဓိပ္ပါယ် ဂၠးတိ။ Htawmonzel (ဓရီု)
- highland
- 1. Any elevated region of land, often one that is mountainous or situated atop a plateau. The term is sometimes reserved for relatively low-elevation mountain ranges or foothills.
- 2. Any area of land (mountainous or otherwise) that is higher in elevation relative to another area. In this sense, the term is often used as a conditional descriptor to distinguish related habitats or ecosystems, especially freshwater riparian areas, on the basis of elevation above sea level.
- highway
- Any major public or private road or other thoroughfare on land, especially one that is paved and capable of supporting high-capacity, rapid transit between populated places.
- hill
- Any landform that extends above the surrounding terrain. A hill is generally considered less steep than a mountain.
- hillock
- A small hill.
- hinterland
- An area that is tributary to a place and linked to that place through lines of exchange or interaction.
- historical geography
- A branch of human geography that studies the ways in which geographic phenomena have changed over time, especially (though not necessarily limited to) geographic change as it relates to human activity.
- hogback
- horizon
- The apparent line that separates the ground from the sky, dividing all visible directions into two categories: those that intersect the Earth's surface and those that do not. When not obscured by buildings, trees, or mountains, the true horizon can be useful in navigation and determining positional orientation.
- horn
- A mountain formed by the back-to-back abutment of three or four adjacent cirques, leaving a distinctly pyramidal peak.
- horst
- A raised block of the Earth's crust, bounded by parallel escarpments or faults, that has been displaced upward or has remained stationary while adjacent blocks on either side, known as grabens, have been displaced downward. Horsts and grabens often occur side-by-side in a repeated series of vertical displacements.
- hotspot
- An area in the middle of a lithospheric plate where magma rises from the mantle and erupts at the Earth's surface. Volcanoes sometimes occur above a hotspot.
- human geography
- The branch of geography that studies humans and their communities, cultures, economies, and interactions with the environment by examining their relations with and across space and place. Along with physical geography, it is one of the two major sub-fields of geography.
- hummock
- A small knoll or mound, typically less than 15 မဳတာs (49 ft) in height and situated above an otherwise level ground surface.
- humus
- Partially decomposed organic soil material.
- hydrography
- The study of the surface waters of the Earth.
- hydrosphere
- The totality of the water found on, under, and above the Earth's surface in liquid, solid, and gaseous forms, including all oceans, lakes, rivers, and streams, as well as all ice and glaciers and subsurface groundwater. Some definitions restrict the hydrosphere to liquid water only, instead placing solid forms in the cryosphere and gaseous forms in the atmosphere.
- hypsography
- The geographic representation on a map of features related to elevation, altitude, and other measures of height above a reference surface.
- hypsometry
- The study or measurement of land elevation relative to mean sea level. Hypsometry is the terrestrial equivalent of bathymetry.
- ice age
- A time of widespread glaciation, such as the Pleistocene Epoch.
- ice cap
- A flattened, often dome-shaped mass of ice that covers less than 50,000 စတုရံ မဳkiloတာs (19,000 sq mi) of land area and is not constrained by topographical features such as mountains; larger masses of ice are termed ice sheets. Contrast polar ice cap.
- ice sheet
- A mass of glacial ice that covers more than 50,000 စတုရံ မဳkiloတာs (19,000 sq mi) of land area; smaller masses of ice may be termed ice caps or ice shelves. The two polar ice sheets are the only ice sheets that currently exist on Earth.
- ice shelf
- A large floating platform of ice formed when a glacier or ice sheet in a coastal area flows onto the ocean surface. By contrast, sea ice is formed directly over the water and is typically much thinner.
- iceberg
- A large chunk of fresh water ice which has broken away from a larger body of ice (such as a glacier or ice shelf) and is floating freely in open water.
- igneous rock
- Rock formed when molten (melted) materials harden.
- impact crater
- A type of crater formed by the hypervelocity collision of a solid astronomical body, such as a meteor, with the Earth's surface. Unlike volcanic craters, impact craters typically have raised rims higher in elevation and depressed floors lower in elevation than the surrounding terrain.
- impoundment
- 1. Another name for a dam that impounds a body of water.
- 2. The reservoir created by such a dam.
- Inertia Costs of Location
- Costs borne by an activity because it remains located at its original site, even though the distributions of supply and demand have changed.
- inlet
- An indentation of a shoreline, usually long and narrow, which often leads to an enclosed body of salt water, such as a sound, bay, lagoon, or marsh.
- inselberg
- An isolated rocky hill, knob, ridge, or small mountain that rises abruptly from a virtually level surrounding plain. Compare mogote.
- insular
- Of or relating to an island, or suggestive of the isolated condition of an island.
- integrated drainage
- A drainage pattern in which stream systems have developed to the point that all parts of the landscape drain into some part of a stream and to a common base level, the initial or original surfaces having essentially eroded away entirely, such that few or no closed drainage systems are present.
- integrated geography
- The branch of geography that describes and explains the spatial aspects of interactions between human individuals or societies and their natural environment.
- intercardinal directions
- The set of four intermediate directions used in cartography and navigation, each of which is located halfway between a pair of cardinal directions: northeast (NE), southeast (SE), southwest (SW), and northwest (NW). They are often included in the compass rose and are used to define further subdivisions such as the secondary-intercardinal directions.
- interfluve
- A narrow, elongated, and plateau-like or ridge-like landform between two valleys, or an area of higher ground between two rivers in the same drainage basin.
- intermediate directions
- See intercardinal directions.
- International Date Line
- A line of longitude generally 180 degrees east and west of the Prime Meridian. The date is one day earlier to the east of the line.
- international waters
- intervening opportunity
- The existence of a closer, less expensive opportunity for obtaining a good or service, or for a migration destination. Such opportunities lessen the attractiveness of more distant places.
- Intracoastal Waterway (ICW)
- A system of navigable inland waterway channels, maintained through dredging and sheltered for the most part by a series of linear offshore islands, that follows the Atlantic and Gulf Coasts of the United States more than 4,800 kiloမဳတာs (3,000 mi) from Boston, Massachusetts, around the southern tip of Florida, to Brownsville, Texas.
- inverted river delta
- island
- Any piece of sub-continental land that is entirely surrounded by water.
- islet
- A very small island.
- isopleth
- Any line on a map connecting places of equal value. These values may express physical or natural quantities, such as elevation above sea level (as with contour lines), or quantities related to social or economic statistics, such as population, wealth, or transport costs.
- isthmus
- A narrow piece of land connecting two larger land areas across an expanse of water by which they are otherwise separated.
- jurisdiction
- 1. The right and power to apply the law in a particular place or within a defined field of responsibility.
- 2. The geographical area to which such authority applies.
- jhum cultivation
- Clear-cutting and/or setting fire to an area of land so it can be used for farm cultivation.
- jungle
- An area covered with dense vegetation dominated by large trees, often tropical.
- kame
- An irregularly shaped hill or mound composed of sand, gravel, and glacial till which accumulates in a depression on a retreating glacier and is subsequently deposited on the land surface with further melting of the glacier. Kames are often associated with kettles.
- karst
- An area possessing surface topography resulting from the underground solution of subsurface limestone or dolomite.
- kettle
- A shallow, sediment-filled body of water formed by blocks of ice calving from a retreating glacier, or by draining floodwaters.
- key col
- knickpoint
- 1. A point of abrupt inflection in the longitudinal profile of a river or its channel or valley, such as occurs at a waterfall.
- 2. Any interruption or break in the character of a slope.
- knob
- A peak or projection from the top of a hill or mountain, or any rounded protrusion of land, especially a small but prominent or isolated hill with steep sides; a boulder or an area of resistant rock protruding from the side of a hill or mountain. The term is used primarily in the southern United States.
- knoll
- See hillock.
- kolk
- 1. A violently rotating underwater vortex capable of plucking and scouring depressions in bedrock, which may leave behind distinct pits or lakes known as rock-cut basins or potholes.
- 2. Another name for a bog pond.
- lacustrine plain
- A nearly level land area formed by the infilling of a lake with sediment and the complete drainage or evaporation of water from the lake, leaving the deposited sediments behind.
- lagoon
- A small area of water connected to the ocean but otherwise blockaded by one or more islands.
- lahar
- See mudflow.
- lake
- A body of water localized in a basin and surrounded entirely by land. Lakes are often defined as separate from any river or stream that serves to feed or drain them.
- land bridge
- Any piece of land connecting larger land areas that are otherwise separated by water, especially one over which living organisms, such as terrestrial animals and plants, are able to cross and thereby colonize previously inaccessible lands. Land bridges may be created by falling sea levels, tectonic activity, or post-glacial rebound. Compare isthmus.
- land cover
- The physical material present on the surface of the Earth, including categories such as vegetation (grasslands, shrubs, forests, etc.), bare ground, water, asphalt and artificial surfaces, and many others.
- landform
- A natural feature of the solid surface of the Earth. A combined set of landforms makes up the terrain of a given area, and their arrangement in a landscape is known as topography.
- landmark
- Any natural or artificial feature that is recognizable enough to be used for navigation; a feature that stands out enough from its environment to be visible across long distances.
- landmass
- Any large contiguous area of land typically surrounded by an ocean or sea. Compare continent.
- landscape
- 1. A broad or distinct area of land consisting of a collection of landforms which define a general geomorphologic form or setting, e.g. a mountain range, valley, plain, coast, etc. Landforms within a landscape are spatially associated but may vary in formation processes and age.
- 2. The visible features of an area of land, its landforms, and how they integrate with natural or man-made features. In the broadest sense, landscapes may include geophysical landforms such as hills and mountains; bodies of water such as rivers, lakes, and the sea; living elements of land cover such as vegetation; human elements such as buildings, structures, and various forms of land use; and transitory elements such as lighting and weather conditions. They reflect both physical origins and the cultural overlay of human presence in a living synthesis of people and place.
- lateral blast
- A sideways-directed explosion from the side or summit of a volcano.
- latitude
- A measure of distance north or south of the Equator. One degree of latitude equals approximately 110 kiloမဳတာs (68 mi). Lines of latitude, also called circles of latitude or parallels, are the imaginary lines that cross the surface of the Earth in an east-west direction (parallel to the Equator) and measure how far north or south of the Equator a place is located.
- lava
- The term used for magma once it has erupted onto the Earth's surface.
- leaching
- A process of soil nutrient removal through the erosive movement and chemical action of water.
- lee
- The side or slope of a physical feature (such as a hill or mountain) which faces downwind, i.e. away from the direction in which the wind is blowing, or which faces away from an advancing glacier or ice sheet. The lee side is often sheltered by the topography from exposure to the wind and any moisture it brings.
- leeward
- Toward the lee side; sheltered from the wind; the direction downwind from a point of reference. Contrast windward.
- legend
- A key for understanding the meanings of the symbols or pictures on a map.
- LEDC
- An acronym for Less Economically Developed Country.
- levee
- An elongated naturally occurring ridge or an artificially constructed wall or barrier which regulates water levels in areas prone to flooding. It is usually earthen and often parallel to the course of a river or a coastline.
- lithosphere
- The Earth's hard, outermost shell. It comprises the crust and the upper part of the mantle. It is divided into a mosaic of 16 major slabs or plates, which are known as lithospheric plates or tectonic plates.
- lithospheric plates
- A series of rigid slabs (16 major ones at present) that make up the Earth's outer shell. These plates float on top of a softer, more plastic layer in the Earth's mantle.
- loam
- A type of easily worked, highly fertile soil composed of clay, silt, and sand in an approximate ratio of 20:40:40. Loams generally heat rapidly, are well-aerated, and drain neither too quickly nor too slowly.
- location
- A particular point or place in physical space. Compare absolute location.
- location theory
- A group of theories which seek to explain the siting of economic activities in particular locations.
- loess
- A soil made up of small particles that were transported by the wind to their present location.
- longitude
- A measure of distance east or west of the Prime Meridian, a line drawn between the North and South Poles and passing through the Royal Observatory at Greenwich, England. Lines of longitude, also called meridians, are the imaginary lines that cross the surface of the Earth in a north-south direction (parallel to the Prime Meridian) and measure how far east or west of the Prime Meridian a place is located.
- longshore drift
- lowland
- Any area of land that is lower in elevation relative to another area. The term is often used as a conditional descriptor to distinguish related habitats or ecosystems, especially freshwater riparian areas, on the basis of elevation above sea level. Lowland areas are usually relatively flat and characterized by slow-flowing waterways and alluvial plains. Contrast upland.
- maar
- A broad, shallow, flat-bottomed volcanic crater created by an eruption involving groundwater coming into contact with magma. Maars commonly have low rims and subtle relief and characteristically fill with water to form crater lakes.
- machair
- magma
- Molten rock containing liquids, crystals, and dissolved gases that forms within the upper part of the Earth's mantle and crust. When erupted onto the Earth's surface, it is called lava.
- magnetic north
- The direction a compass points, towards the Magnetic North Pole. Magnetic north differs from true north and grid north.
- main stem
- The primary downstream channel of a river as contrasted with its tributaries. Virtually all of the water in a river's drainage basin eventually flows through the main stem.
- mainland
- A term used to denote a contiguous landmass or political territory relative to its politically associated but geographically remote outlying territories. It is variously used to refer to the continental (i.e. non-insular) part of a polity relative to its exclaves or oceanic islands; or to the largest or most politically, economically, and/or demographically significant island within an island nation. For example, continental Europe is often considered "the mainland" relative to the British Isles, while the island of Great Britain is considered "the mainland" relative to Northern Ireland and the many smaller islands that constitute the United Kingdom.
- makhtesh
- A deep, closed valley (usually drained by a single wadi) surrounded by steep walls of resistant rock and superficially resembling a crater. The term is used primarily in the deserts of Israel and Egypt.
- mammilated
- Smooth and rounded in appearance, used of various landforms of different sizes from individual rocks to entire landscapes.
- mantle
- A zone in the Earth's interior between the crust and the core that is 2,900 kiloမဳတာs (1,800 mi) thick. The lithosphere is composed of the topmost 65–70 kiloမဳတာs (40–43 mi) of the mantle and the crust.
- map
- A picture of a place that is usually drawn to scale on a flat surface.
- map projection
- A systematic transformation of the latitudes and longitudes of locations from the surface of a three-dimensional shape, such as a sphere or an ellipsoid, into locations on a two-dimensional plane. Maps of locations on the Earth require map projections to represent features in a convenient format that is easy to view and interpret, though all map projections necessarily distort the true properties of the Earth's surface to some degree.
- maritime climate
- A climate strongly influenced by an oceanic environment, typically found on islands and the windward shores of continents. It is characterized by small daily and yearly temperature variation and high relative humidity.
- marsh
- A wetland dominated by herbaceous rather than woody plant species and often found at the edges of lakes and streams, where it forms a transition between the aquatic and terrestrial ecosystems.
- massif
- 1. Any section of the Earth's crust which is demarcated by faults or flexures and tends to retain its internal structure while being displaced as a whole.
- 2. A single large mountain mass or compact group of connected mountains forming an independent portion of a mountain range.
- meander
- One of a series of regular sinuous curves, bends, loops, turns, or windings in the main channel of a river, stream, or other watercourse. Meanders are produced by the repetitive upstream erosion and downstream deposition of sediments along the banks of a watercourse as the water flows back and forth across the axis of a valley or floodplain.
- meander scar
- A typically crescent-shaped incision in a bluff or valley wall formed by the remnants of a dry, abandoned meander.
- MEDC
- An acronym for More Economically Developed Country.
- Mediterranean climate
- Any climate characterized by mild, rainy winters and hot, dry summers, as experienced in the Mediterranean Basin.
- megacity
- megalopolis
- A chain of roughly adjacent metropolitan areas which have merged into a very large and heavily populated urban complex. See conurbation and metropolitan coalescence.
- megaregion
- meridian
- See longitude.
- mesa
- An isolated, relatively flat-topped natural elevation, usually more extensive than a butte and less extensive than a plateau.
- metamorphic rock
- Rock that has been physically altered by heat and/or pressure.
- metes and bounds
- A system of land survey that defines land parcels according to visible natural landscape features and distance. The resultant field pattern is usually very irregular in shape.
- metropole
- metropolis
- A large city or conurbation which is considered a significant economic, political, or cultural center for a country or geographic region and/or an important hub for regional or international connections and communications.
- metropolitan area
- A region consisting of one or more densely populated urban cores (often a metropolis) and its less populous surrounding territories, including satellite cities, towns, and intervening rural areas, all of which are socioeconomically tied to the core as typically measured by commuting patterns. A metropolitan area usually comprises multiple neighborhoods, jurisdictions, and municipalities, with its inhabitants sharing industry, housing, and many other forms of infrastructure.
- metropolitan coalescence
- The merging of the urbanized parts of separate metropolitan areas; a megalopolis is a result of this process.
- metropolitan state
- mogote
- An isolated, rounded, steep-sided hill composed of either limestone, marble, or dolomite and surrounded by nearly flat alluvial plains, especially as found in tropical regions.
- mole
- A long, massive, man-made stone or earthen structure used as a pier or breakwater, or as a causeway between places separated by water, but designed to prevent the free movement of water underneath it (unlike a true pier).
- monadnock
- See inselberg.
- moor
- An upland habitat and ecoregion characterized by low-growing vegetation on acidic soils and generally referring to uncultivated hills but also including low-lying wetlands.
- moraine
- The rocks and soil carried and deposited by a glacier. An "end moraine," either a ridge or low hill running perpendicular to the direction of ice movement, forms at the end of a glacier when the ice is melting.
- mound
- Any heaped pile of earth, gravel, sand, rocks, or debris, typically with a rounded top and of topographically higher elevation than its immediate surroundings.
- mountain
- A large landform that rises prominently above the surrounding land in a limited area, usually in the form of a rocky peak with great vertical relief; a mountain is generally considered steeper than a hill. Mountains are formed by volcanic or tectonic forces and erode slowly through the actions of rivers, glaciers, and weathering. Most exist within extensive mountain ranges.
- mountain pass
- mountain range
- A series of neighboring mountains or hills, often closely arranged in a line and connected by high ground. Individual mountains within the same mountain range are usually the result of the same orogeny, and often (though not always) share a common form, alignment, and geology.
- mouth
- 1. The place where a river or stream flows into another body of water, such as a lake or another river but especially a sea or ocean. Deltas and estuaries occur near the mouths of rivers.
- 2. The lower or downstream end or the most accessible entrance of a valley, canyon, ravine, or cave.
- mudflat
- A type of coastal wetland consisting of exposed layers of bay mud formed by the deposition of silts, clays, and marine animal detritus by tides or rivers. Mudflats usually form within the intertidal zone of relatively sheltered areas such as bays and lagoons.
- mudflow
- A flowing mixture of water and debris (intermediate between a volcanic avalanche and a water flood) that forms on the slopes of a volcano.
- multilingual
- The ability to use more than one language when speaking or writing. This term often refers to the presence of more than two populations of significant size within a single political unit, each group speaking a different language as their primary language.
- municipal corporation
- municipality
- A type of general-purpose urban administrative subdivision having corporate status and powers of self-government or jurisdiction as granted by national and/or state laws to which it is subordinate. Municipalities are often included within but usually distinguished from larger administrative divisions such as counties, though the nature of their territorial boundaries and political jurisdictions can vary considerably in different parts of the world.
- muskeg
- Another name for a bog, used primarily in Alaska and western Canada.
- nadir
- narrows
- A land or water passage that is confined or restricted by its narrow breadth, often a strait or a water gap.
- nation
- A stable community of people formed on the basis of a common geographic territory, language, economy, ethnicity, or psychological make-up as manifested in a common culture.
- national mapping agency
- A governmental agency which manages, produces, and publishes topographic maps, geographic data, and sometimes cadastral information that is specific to an individual nation or political territory, such as the United Kingdom's Ordnance Survey.
- national park
- A type of protected area created and managed as a public park by a national governmental authority for conservation purposes. Though individual governments designate national parks differently, they usually share the common goal of preserving natural or semi-natural landscapes (often wilderness) for posterity and as symbols of national pride.
- natural landscape
- The original landscape that exists before it is acted upon by humans. Contrast cultural landscape.
- 1. The determination of position and direction, generally by comparing the navigator's position to known locations or patterns.
- 2. The process of monitoring and controlling the movement of a vehicle or craft from one place to another.
- neatline
- A line separating the main body of a map from the map's margin. On a standard quadrangle map, the neatlines are the meridians and parallels delimiting the quadrangle.
- neighborhood
- A geographically localized community within a larger city, town, suburb, or rural area, particularly one which supports considerable face-to-face interactions between residents.
- nodal region
- A region characterized by a set of places connected to another place by lines of communication or movement.
- North Geographic Pole
- The point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is the northernmost point on Earth, directly opposite the South Geographic Pole, and defines the direction of true north at a latitude of 90 degrees North; its longitude can be assigned any degree value. Unlike the South Pole, the North Pole is not located on a continental landmass but in the middle of the Arctic Ocean. See also North Magnetic Pole.
- ပၞိဟ်ပထဝဳသၟဝ်ကျာ (North Geographic Pole)၊ ပၞိဟ်သၟဝ်ကျာ (North Pole) ပ္ဍဲအရေဝ်မန် ဂွံဆဵုကေတ် ပဏိဟ်တိ၊ ဗောဓိပၞိဟ်တိ (သက်လောန်၊ အဘိဓာန်၉၅၉)၊ ညးတမၠာတအ် ညးတအ် ပတှ်ေကေတ် ဂၠးတိပိုယ် ခပေဟ်တုဲ ခဍမ်ဒၟံင်။ တုဲပၠန် ညးတအ်စှ်ေစိုတ် တၞံဇြဲဗောဓိ ဒၞာဲကျာ်ဒှ်ဂှ် ဒှ်ဒၞာဲလဒေါဝ်ဓဝ်ဓဝ်ဂၠးတိရ။ ဂွံဆဵုကေတ် မွဲဒၞာဲပၠန်ဂှ် "သၟိင်အိန် စှ်ေသပေါတ်ပဏိဟ်သၟတ်ဗြဴတုဲ သၟတ်ဗြဴ တန်အာပတိသန္ဓိရ" (ပေါရဏာံပေါရဒံါ အစွောအ်၊ - သက်လောန်အဘိဓာန် ၉၅၉) အဓိပ္ပါယ်ဒၞာဲဏအ်လေဝ် သၟိင်အိန် သပေါတ် လဒေါဝ်ဗုင်သၟတ်ဗြဴဂှ်ရ။ ရံင်ကဵု အရေဝ်ဝွံတုဲ မအရေဝ်မ္ဂး North Pole ဂှ် ပၞိဟ်သၟဝ်ကျာ South Pole ပၞိဟ်သၠုင်ကျာ ဗီုဏအ် ပိုယ်တအ် ကော်ဂွံရ။--Htawmonzel (ဓရီု) ၁၇:၁၄၊ ၁၆ အဝ်ဂေတ် ၂၀၂၀ (+0630)
- North Geomagnetic Pole
- The point in the Northern Hemisphere where the axis of a theoretical simplified dipole passing through the center of the Earth would intersect the Earth's surface. It is antipodal to the South Geomagnetic Pole. Because of the fluid nature of the Earth's molten core, the true axis of the Earth's magnetic field is not a perfect dipole, and so the Geomagnetic Poles and the actual Magnetic Poles lie some distance apart.
- North Magnetic Pole
- The point in the Northern Hemisphere at which the Earth's magnetic field points vertically downward. It is close to but distinct from the Geographic North Pole and the Geomagnetic North Pole, and its precise location varies considerably over time due to frequent magnetic changes in the Earth's core. Its counterpart in the Southern Hemisphere is the South Magnetic Pole, though the two poles are not directly opposite each other.
- Northern Hemisphere
- The half sphere of the Earth that is north of the Equator. It is opposite the Southern Hemisphere.
- northing
- nubbin
- nunatak
- oasis
- A combination of a human settlement and an area of cultivated vegetation in an otherwise desolate desert or semi-desert environment, made fertile when sources of fresh water, such as underground aquifers, irrigate the surface naturally or via man-made wells.
- ocean
- The vast, contiguous body of salt water covering more than 70% of the Earth's surface area and surrounding the continental landmasses, or any portion of this larger body of water that is divided and distinguished from the other portions, each of which is called an ocean, by the presence of the landmasses.
- ocean current
- ocean floor
- See seabed.
- ocean trench
- A long, narrow, very deep depression in the ocean floor where, at the junction of two tectonic plates, one plate is subducted steeply beneath the other, often penetrating the mantle.
- open range
- A cattle- or sheep-ranching area characterized by a general absence of fences and in which livestock are allowed to roam freely.
- ordinal directions
- See intercardinal directions.
- orienteering
- orographic rainfall
- Precipitation that results when moist air is lifted over a topographic barrier, such as a mountain range.
- outcrop
- Any visible exposure of bedrock or ancient superficial deposits on the surface of the Earth, or more generally, any bare, rocky surface that is topographically distinct from the surrounding terrain. Outcrops occur frequently in places where the rate of erosion exceeds the rate of weathering, such as on steep hillsides and mountains, river banks, and coastlines.
- outwash
- Rocky and sandy surface material deposited by melted water that flows from a glacier.
- overburden
- Material covering a mineral seam or bed that must be removed before the mineral can be removed in strip mining.
- oxbow
- 1. A wide U-shaped meander in a river or stream.
- 2. The lake formed when a meander is cut off from the main stem of the river, creating a separate body of water.
- palisade
- 1. A wall of wooden stakes used as a defensive barrier.
- 2. A line of bold cliffs, especially one showing basaltic columns.
- panhandle
- See salient.
- panhole
- A rounded or circular depression eroded into flat or gently sloping cohesive rock, typically shallow and ranging in diameter from a few centimeters to several meters, that is capable of collecting and holding rainwater and snowmelt. The term is sometimes used interchangeably with pothole, though the latter may also refer to distinct geological features.
- parish
- pediplain
- peneplain
- peninsula
- A piece of land surrounded by water along the majority of its border while still being connected to a mainland from which it extends.
- permafrost
- A permanently frozen layer of soil; permanently frozen ground at high latitude and high elevation.
- photogrammetry
- 1. The science and technology of obtaining reliable information about physical objects and environments through the process of recording, measuring, and interpreting photographic images (usually aerial or orbital ones) and patterns of electromagnetic radiant imagery and other phenomena.
- 2. The science of extracting three-dimensional measurements from two-dimensional data, such as images.
- physical geography
- The branch of geography that studies processes and patterns in the natural environment, such as the atmosphere, hydrosphere, geosphere, and biosphere, as opposed to the cultural or built environment. Along with human geography, it is one of the two major sub-fields of geography.
- physiographic region
- A portion of the Earth's surface with a common topography and common morphology.
- physiography
- Another name for physical geography.
- piedmont
- 1. Any geographic region lying or formed at the base of mountains.
- 2. In the Southeastern United States, a broad region extending from the Blue Ridge Mountains to the Atlantic coastal plain.
- pit crater
- A type of crater formed by the sinking or collapse of the surface lying above a void or empty chamber. Pit craters are similar to calderas and are often associated with volcanic activity, but lack the ejecta deposits and lava flows of volcanic craters.
- place identity
- plain
- Any broad, flat expanse of land that generally does not show significant variation in topography or elevation.
- plate tectonics
- A geologic theory that the bending (folding) and breaking (faulting) of the solid surface of the Earth results from the slow movement of large sections of that surface called plates.
- plateau
- A large area of relatively flat terrain that is significantly higher in elevation than the surrounding landscape, often with one or more sides with steep slopes.
- platted land
- Land that has been divided into surveyed lots.
- plumb line
- plural society
- A situation in which two or more culture groups occupy the same territory but maintain their separate cultural identities.
- point bar
- polar circle
- Either of the two circles of latitude enclosing the Earth's polar regions: the Arctic Circle in the Northern Hemisphere and the Antarctic Circle in the Southern Hemisphere.
- polar ice cap
- Either of the two very large regions near the Earth's geographical poles that are seasonally or persistently covered in ice, which occurs because high-latitude regions receive less direct solar radiation than other regions and therefore experience much lower surface temperatures. The Earth's polar ice may cover both land and sea, and varies in size seasonally and with long-term climate change. They typically cover a much larger area than true ice caps and are more correctly termed ice sheets.
- polar region
- Either of the two high-latitude regions surrounding the Earth's geographical poles (the North and South Poles), which are characterized by frigid climates and extensive polar ice caps. The polar region of the Northern Hemisphere is often simply called the Arctic and that of the Southern Hemisphere is called the Antarctic.
- pole of inaccessibility
- political geography
- The study of both the spatially uneven outcomes of political processes and the ways in which political processes are themselves affected by spatial structures. A sub-discipline of human geography, its primary concerns can be summarized as the relationships between people, state, and territory.
- polynodal
- Many-centered.
- polynya
- An area of unfrozen seawater surrounded by an otherwise contiguous area of pack ice or fast ice. Polynyas are often formed along polar coastlines through the action of katabatic winds, but may also form in the open ocean.
- pond
- A natural or artificial body of standing water that is usually smaller than a lake.
- populated place
- A place or area with clustered or scattered buildings and a permanent human population (a city, settlement, town, or village) that is referenced with geographic coordinates.
- population
- A collection of organisms of the same group or species which live in a particular geographical area. In the context of geography, it often refers to a collection of humans and is represented at the most basic level as the number of people in a given geographically or politically defined space, such as a city, town, region, country, or the entire world.
- population geography
- A branch of human geography that studies the ways in which spatial variations in the composition, distribution, migration, and growth of populations are related to the nature of places. This often involves factors such as where populations are found and how the size and composition of these populations is regulated by the demographic processes of fertility, mortality, and migration.
- positioning system
- post-industrial
- An economy that gains its basic character from economic activities developed primarily after manufacturing grew to predominance. Most notable would be quaternary economic patterns.
- pothole
- 1. Any smooth, bowl-shaped or cylindrical hollow, generally deeper than it is wide, that is carved into the rocky bed of a watercourse such as a stream or river. Fluvial potholes are created by the grinding action of stones or coarse sediment kept in perpetual motion in the same spot by the turbulence of the current. The term is also used to refer to plunge pools beneath waterfalls, which are created by similar processes. See also kolk.
- 2. A vertical or steeply inclined karstic shaft in a limestone deposit.
- 3. In the Great Plains of North America, a shallow depression, generally less than 10 ဨကs (4.0 ha) in area, occurring between dunes or on morainic relief on a prairie and often filled by an intermittent pond or marsh.
- 4. Another name for a kettle.
- 5. Another name for a panhole.
- prairie
- A type of temperate grassland ecosystem dominated by a characteristic composition of grasses, herbs, and shrubs, rather than by trees. The term is used primarily in North America, but similar ecosystems can be found across the world.
- Precambrian rock
- The oldest rocks, generally more than 600 million years old.
- presque-isle
- A peninsula connected to the mainland by an extremely narrow neck of land such that the land at its distal end is very close to being an island. See also tied island.
- prevailing winds
- The direction from which winds most frequently blow at a specific geographic location.
- primary sector
- That portion of a region's economy devoted to the extraction of basic materials (e.g., mining, lumbering, agriculture).
- Prime Meridian
- The imaginary line running from north to south through the Royal Observatory in Greenwich, England which is assigned a longitude of 0 degrees and is therefore used as the reference point for all other lines of longitude.
- promontory
- A raised mass of land that projects into a lowland or a body of water. Compare headland and cape.
- protected area
- Any clearly defined geographic space in which human occupation or the exploitation of resources is limited or forbidden through legal or other effective means because of the area's recognized natural, ecological, cultural, or historical value.
- province
- A type of second-level administrative division within a country or federal state.
- psychogeography
- public land
- Any land area held and managed in the public domain by a federal or local government.
- pueblo
- A type of Indian village constructed by some tribes in the southwestern United States. A large community dwelling, divided into many rooms, up to five stories high, and usually made of adobe. This is also a Spanish word for town or village.
- quadrangle
- A standard division of the Earth's surface area used in maps produced by the United States Geological Survey. Quadrangles are four-sided polygons of varying size, depending on the map series; for example, 7.5-minute quadrangles divide the mapped surface into quadrilaterals measuring 7.5 minutes (0.125 degrees) of latitude by 7.5 minutes of longitude, with each 7.5-minute map showing the topographical detail within one particular quadrilateral of this size. Because the boundaries of quadrangles are based on lines of latitude and longitude, the northern and southern limits of a quadrangle map are not straight lines, and the eastern and western limits are usually not parallel; the actual surface area covered by each map varies with the latitudes depicted.
- quarry
- A place from which stone, rock, sand, gravel, slate, or aggregate is excavated from the ground. Also sometimes called an open-pit mine.
- rail gauge
- The distance between the two rails of a railroad.
- rain shadow
- An area on the leeward (downwind) side of a mountain or mountain range that receives greatly diminished precipitation.
- rainforest
- Any forest characterized by abundant rainfall, dense layers of vegetation, and extremely high biodiversity. Rainforests are found in both tropical and temperate regions. The term jungle is sometimes used to refer to a tropical rainforest.
- ravine
- A fluvial slope landform of relatively steep sides, sometimes with an intermittent stream flowing along the downslope channel. Ravines are typically considered narrower and shallower than canyons, larger than gullies, and smaller than valleys.
- re-entrant
- See draw.
- reef {{defn|A submerged ridge-like or mound-like structure built by sedentary calcareous organisms, especially corals, in shallow marine waters, and consisting primarily of their skeletal remains, though often still supporting living colonies as well. Reefs may also be partially composed of rocks, sand, gravel, or seashells. They are locally prominent above surrounding sediments deposited on the sea floor, rising to or nearly to the water's surface.
- reference ellipsoid
- A mathematically defined surface that approximates the geoid for use in spatial reference systems or geodetic datum definitions. Because of their relative simplicity, reference ellipsoids are used in geographic applications as preferred surfaces on which geodetic network computations are performed and point coordinates such as latitude, longitude, and elevation are defined.
- region
- An area having some characteristic or characteristics that distinguish it from other areas; a territory that is of interest to people, for which one or more distinctive traits are used as the basis for its identity.
- regiopolis
- A city located outside the core of a metropolitan area that serves as an independent driving force for political, economic, or cultural development within a larger region. Contrast metropolis.
- relief
- See terrain.
- relief map
- See topographic map.
- remote sensing
- The gathering of information about an object or place from a remote location (i.e. without making physical on-site observations), most commonly by the use of satellite- or aircraft-based electromagnetic sensor technologies.
- reservoir
- An artificial lake or an artificially enlarged natural lake that is used to store water. Reservoirs are often created by the construction of a dam or lock in a natural drainage basin.
- resource
- Anything that is both naturally occurring and of use to humans.
- retroreflector
- rhumb line
- A line drawn on the surface of a sphere (or on an idealized representation of the Earth) which crosses all meridians of longitude at the same angle, and which therefore has constant bearing relative to true or magnetic north.
- ria
- The seaward end of a river valley which has been flooded as a result of a rise in sea level.
- ribbon lake
- A long, narrow, finger-shaped lake, especially one found in a glacial trough and dammed by a rock bar or moraine.
- ridge
- An elongated raised landform which forms a continuous elevated crest for some distance, such as a chain of hills or mountains. The line formed by the highest points, with only lower terrain immediately to either side, is called the ridgeline.
- riegel
- An outcrop of resistant bedrock that forms a bar across a glacial trough and often acts as a dam to impound the waters of a lake.
- rift valley
- A valley that has formed along a long, narrow continental trough bounded by normal faults; a graben of regional size.
- riparian rights
- The rights of water use possessed by a person owning land containing or bordering a watercourse or lake.
- riparian zone
- river
- A natural watercourse, usually fresh water, that flows towards an ocean, sea, lake, another river, or in some cases into the ground.
- river pocket
- An area of land enclosed within the bend of a river, especially where the bend is extended or pronounced and the only road access is along the isthmus. The term is used primarily in Australia
- riverine
- Located on or inhabiting the banks or the area adjacent to a river or lake. Compare riparian.
- roadstead
- rural
- An adjective describing any geographic area located outside areas of significant human population such as towns and cities; all population, housing, and territory not included within an urban area is often said to be rural. Rural areas are typified by low population densities, very small settlements, and expansive areas of agricultural land or wilderness.
- saddle
- salient
- Any narrow, elongated protrusion of a larger territory, either physical or political, such as a state.
- salt pan
- A large, flat expanse of land naturally covered with salt and/or other minerals, usually to the exclusion of virtually all vegetation. Salt pans are common in deserts, where they form by the precipitation of dissolved mineral solids as a large body of water evaporates.
- salt water
- Any naturally occurring water, especially the water from a sea or ocean, characterized by high concentrations (between 3 and 5% by volume) of dissolved salts, primarily sodium and chloride ions, relative to fresh water. Salt water in the Earth's oceans has an average salinity of about 3.5%; it is both denser and freezes at a lower temperature than fresh water.
- scale
- The relationship between a linear measurement on a map and the distance it represents on the Earth's surface.
- scarp
- A steep cliff or steep slope, formed either because of faulting or by the erosion of inclined rock strata.
- sea
- 1. Any large body of salt water surrounded in whole or in part by land.
- 2. Any large subdivision of the World Ocean. "The sea" is the colloquial term for the entire interconnected system of salty bodies of water, including oceans, that covers the Earth.
- sea level
- The average level of the surface of one or more of Earth's oceans from which heights such as elevation and altitude are commonly measured. Often called mean sea level (MSL), it is a type of standardized geodetic vertical datum that is used in numerous applications, including surveying, cartography, and navigation. Mean sea level is commonly defined as the midpoint between the mean low and mean high tides at a particular location.
- seabed
- seamount
- A mountain (often a volcano) rising from the ocean floor whose summit does not reach the water's surface and which is therefore entirely submerged and not an island or islet.
- second home
- A seasonally occupied dwelling that is not the primary residence of the owner. Such residences are usually found in areas with substantial opportunities for recreation or tourist activity.
- secondary-intercardinal directions
- The set of eight intermediate directions used in cartography and navigation, each of which is located halfway between a pair of intercardinal directions: north-northeast (NNE), east-northeast (ENE), east-southeast (ESE), south-southeast (SSE), south-southwest (SSW), west-southwest (WSW), west-northwest (WNW), and north-northwest (NNW). They may or may not be explicitly labeled on a compass rose.
- secondary sector
- That portion of a region's economy devoted to the processing of basic materials extracted by the primary sector.
- sector principle
- The principle on which political claims to territory in the polar regions have historically been made, such that the territories are divided into arbitrary wedge-shaped sectors, each one having an apex at the geographic pole and including outer areas of both land and sea extending to a particular latitude. Because of the limited accessibility and generally low material value of both the Arctic and Antarctic, the sector principle has emerged as a means of formally sharing responsibility for these regions between the world's sovereign states.
- sedimentary rock
- Rock formed by the hardening of material deposited in some process; most commonly sandstone, shale, and limestone.
- seismograph
- A scientific instrument that detects and records vibrations (seismic waves) produced by earthquakes.
- settlement
- Any place where people live and form communities.
- sheepback
- A rock formation created by the passage of a glacier over underlying bedrock, which often results in asymmetrical erosional forms created by abrasion on the upstream side of the rock and plucking on the downstream side.
- shield
- A broad area of very old rocks above sea level that is usually characterized by thin, poor soils and low population densities.
- shield volcano
- A volcano that resembles an inverted warrior's shield. It has long gentle slopes produced by multiple eruptions of fluid lava flows.
- shoal
- A natural submerged ridge, bank, or bar that consists of or is covered by sand or other unconsolidated material and rises from the bed of a body of water to just below or above the surface.
- shore
- The fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. Compare coast.
- sinkhole
- A crater formed when the roof of a cavern collapses, usually found in areas of limestone rock.
- site
- The features of a place related to the immediate environment on which the place is located (e.g. terrain, soil, subsurface, geology, groundwater).
- situation
- The features of a place related to its location relative to other places (e.g., accessibility, hinterland quality).
- slide
- 1. The noticeable track of bare rock or furrowed earth left by the mass movement of soil, mud, snow, or rock under shear stress down a steep slope, as in a landslide or avalanche.
- 2. The mass of material moved or deposited by such an event, and which has become fixed or settled upon the landscape.
- slope
- See grade.
- slough
- A type of wetland – usually a swamp, a shallow lake, or a backwater branching from or feeding into a river – in which water tends to be stagnant or flows only very slowly on a seasonal basis.
- smog
- A mixture of particulate matter and chemical pollutants in the lower atmosphere, usually over urban areas.
- Standard Metropolitan Statistical Area (SMSA)
- A statistical unit of one or more counties that focus on one or more central cities larger than a specified size, or with a total population larger than a specified size. This is a reflection of urbanization.
- snowline
- The lowest elevation at which snow remains from year to year and does not melt during the summer.
- soil horizon
- A distinct layer of soil encountered in vertical section.
- solubility
- The degree to which a substance can be dissolved in another substance; in a geographical context, the characteristic of soil minerals that leads them to be carried away in solution by water (see leaching).
- sound
- 1. A large inlet of a sea or ocean that is larger than a bay, deeper than a bight, and wider than a fjord.
- 2. A narrow sea or ocean channel between two landmasses.
- South Geographic Pole
- The point in the Southern Hemisphere where the Earth's axis of rotation meets its surface. It is the southernmost point on Earth, directly opposite the North Geographic Pole, and is located on continental land in Antarctica at a latitude of 90 degrees South; its longitude can be assigned any degree value. See also South Magnetic Pole.
- South Geomagnetic Pole
- The point in the Southern Hemisphere where the axis of a theoretical simplified dipole passing through the center of the Earth would intersect the Earth's surface. It is antipodal to the North Geomagnetic Pole. Because of the fluid nature of the Earth's molten core, the true axis of the Earth's magnetic field is not a perfect dipole, and so the Geomagnetic Poles and the actual Magnetic Poles lie some distance apart.
- South Magnetic Pole
- The point in the Southern Hemisphere at which the Earth's magnetic field points vertically downward. It is close to but distinct from the Geographic South Pole and the Geomagnetic South Pole, and its precise location varies considerably over time due to frequent magnetic changes in the Earth's core. Its counterpart in the Northern Hemisphere is the North Magnetic Pole, though the two poles are not directly opposite each other.
- Southern Hemisphere
- The half sphere of the Earth that is south of the Equator. It is opposite the Northern Hemisphere.
- space economy
- The locational pattern of economic activities and their interconnecting linkages.
- spatial citizenship
- The participation of individuals and groups of laypeople in decision-making about spatial planning and social rules in public spaces through the reflexive production and use of geographic media such as maps, virtual globes, and GIS software, particularly in order to question existing perspectives on the appropriation of space and the actions permitted within that space and to negotiate alternative spatial visions.
- spatial complementarity
- The occurrence of location pairing such that items demanded by one place can be supplied by another.
- spatial interaction
- Movement between locationally separate places.
- spatial reference system (SRS)
- A coordinate-based local, regional, or global system used to locate geographical entities and which defines a specific map projection as well as transformations between different systems.
- spirit level
- spit
- A type of bar or shoal extending from a beach into an ocean or lake and which develops by the deposition of sediment as a result of longshore drift. Spits form where the direction of the shoreline sharply changes direction, such as at a headland, and often develop a "hooked" or recurve shape at their distal ends.
- spreading ridges
- Places on the ocean floor where lithospheric plates separate and magma erupts. About 80 percent of the Earth's volcanic activity occurs on the ocean floor.
- spring
- Any location where water naturally emerges from an underground aquifer to the Earth's surface.
- spur
- A lateral ridge or other salient landform protruding from the side of a hill, mountain, or the main crest of a ridge and typically surrounded on at least three sides by steep hillsides.
- stack
- A coastal landform consisting of a steep and often vertical column or columns of rock above the surface of the sea and formed by erosion due to wave action.
- stand
- An area of vegetation dominated by a single species, e.g. a stand of oak trees.
- state
- A compulsory political organization with a centralized government that maintains a monopoly of the legitimate use of force within a certain geographical territory. See country.
- steppe
- An ecoregion characterized by expansive grassland plains without trees apart from those near rivers and lakes.
- strait
- See channel.
- strath
- A large river valley, typically wider and shallower than a glen. The term is used primarily in Scotland, Australia, and Canada.
- stratovolcano
- A steep-sided volcano built by lava flows and tephra deposits.
- stream
- A natural body of water in which surface water flows between the banks of a channel. Long, large streams are usually called rivers.
- streambed
- The bottom of the channel of a stream or river, usually covered with rocks, sand, or debris and totally devoid of terrestrial vegetation if the stream has flowed recently. The bed is generally considered the part of the channel up to the normal water line, whereas the bank is the part above the water line.
- subduction zone
- The place where two lithospheric plates come together, one riding over the other. Most volcanoes on land occur parallel to and inland from the boundary between the two plates.
- suburban
- An adjective describing a mixed-use or residential area existing either as part of an urban area or as a separate community within commuting distance of a city; a place of this type is called a suburb. Suburbs are often defined by commuter infrastructures and have lower population densities than inner-city neighborhoods.
- suburbanization
- The process by which a human population shifts from urban to suburban residency, or the gradual increase in the proportion of people choosing to live in suburban neighborhoods which act as satellite communities within commuting distance of larger, centralized urban areas. Suburbanization is inversely related to urbanization.
- summit
- A point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, it is a local maximum in elevation. The highest point of a hill or mountain is often referred to as the summit.
- surface water
- Water present on the surface of the Earth, such as in a river, lake, wetland, or ocean, as opposed to subsurface water.
- surveying
- The science, technique, and profession of determining the terrestrial or three-dimensional positions of points on the surface of the Earth and the distances and angles between them. These points are often used to draw maps and establish boundaries for property ownership, construction projects, and other purposes required by civil law.
- swale
- Any shallow channel or trough with gently sloping sides, either natural or artificial. Man-made swales are often designed to manage surface runoff and increase rainwater infiltration.
- swamp
- A forested wetland, often occurring along a large river or on the shores of a large lake.
- syrt
- A denudational highland or elevated flatland in Russia and Central Asia; a kind of dissected plateau.
- taiga
- A moist subarctic coniferous forest that begins where the tundra ends and is dominated by spruces and firs.
- tarn
- A mountain lake or pool of water formed in a cirque excavated by a glacier. A moraine may form a natural dam below a tarn.
- temperature inversion
- An increase in temperature with height above the Earth's surface, a reversal of the normal pattern.
- tephra
- Solid material of all sizes explosively ejected from a volcano into the atmosphere.
- terrain
- The vertical and horizontal dimensions of a land surface, usually as expressed in terms of elevation, slope, and orientation of geographical features.
- territorial waters
- 1. A concept of the Law of the Sea defined as a belt of coastal waters extending at most 12 တိုင်ဍာ်s (22 km) from the designated baseline (usually defined as the mean low-water line) for a coastal state and regarded as the sovereign territory of the state.
- 2. Any area of water over which a state has legal jurisdiction, including internal waters, the exclusive economic zone, and potentially others.
- territory
- A specific area or portion of the Earth's surface; similar to though distinct from a region.
- tertiary sector
- That portion of a region's economy devoted to service activities (e.g., retail and wholesale operations, transportation, insurance).
- thalweg
- The line of lowest elevation within a valley or watercourse. Thalwegs often acquire special significance in political geography because disputed borders along rivers are often defined as the river's thalweg.
- tide
- The periodic rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the Earth's rotation.
- tide pool
- A shallow pool of seawater, supplied regularly by incoming tides, that forms on a rocky intertidal shore.
- tied island
- An island that is connected to a mainland only by a narrow spit or tombolo which may or may not be occasionally submerged.
- till
- See glacial till.
- time distance
- A time measure of how far apart places are (how long does it take to travel from place A to place B?). This may be contrasted with other distance metrics such as geographic distance (how far is it?) and cost-distance (how much will it cost to get there?).
- time geography
- An interdisciplinary perspective, ontological framework, and visual language in which space and time are used as basic dimensions of analysis of dynamic processes and events, including social and ecological interactions, environmental changes, and biographies of individuals.
- time zone
- A region of the globe that observes a uniform standard time for legal, commercial, and social purposes.
- tombolo
- topographic map
- A map that uses contour lines to represent the three-dimensional features of a landscape on a two-dimensional surface.
- topographical relief
- See terrain.
- topographic isolation
- The minimum great-circle distance between the summit of a mountain or hill and a point of equal elevation, representing a radius of dominance in which the summit is the highest point.
- topographic prominence
- A measure of the independence of a mountain or hill defined as the vertical distance between its summit and the lowest contour line encircling it but containing no higher summit within it or, equivalently, the difference between the elevation of the summit and the elevation of the key col. Mountains with high prominence tend to be the highest points in their vicinity.
- topography
- The physical features of a place, or the study and depiction of physical features, including terrain relief.
- toponymy
- The study of placenames (known as toponyms), their origins, meanings, use, and typology.
- tor
- A prominent, free-standing rock outcrop that rises abruptly from the smooth slopes of a gently rounded hill or ridge. In the United Kingdom, the term is also used to refer to the hill itself.
- town
- A medium-sized human settlement that is generally larger than a village but smaller than a city, though the criteria for distinguishing a town vary considerably in different parts of the world.
- township and range
- The rectangular system of land subdivision of much of the agriculturally settled United States west of the Appalachian Mountains, established by the Land Ordinance of 1785.
- transferability
- The extent to which a good or service can be moved from one location to another; the relative capacity for spatial interaction.
- transhumance
- The seasonal movement of people and animals in search of pasture. Commonly, winters are spent in snow-free lowlands and summers in the cooler uplands.
- tree line
- The latitudinal or elevational limit of normal tree growth. Beyond this limit (i.e. closer to the poles or at higher elevations) climatic conditions are too severe for such growth and trees are stunted or entirely absent.
- triangulation
- tributary
- A stream or river that flows into a larger stream or main stem or a lake, rather than directly into a sea or ocean. Contrast distributary.
- Tropic of Cancer
- The northernmost circle of latitude on the Earth at which the Sun appears directly overhead at its culmination, which lies approximately 23.4 degrees north of the Equator. Its southern equivalent is the Tropic of Capricorn.
- Tropic of Capricorn
- The southernmost circle of latitude on the Earth at which the Sun appears directly overhead at its culmination, which lies approximately 23.4 degrees south of the Equator. Its northern equivalent is the Tropic of Cancer.
- tropics
- The region of the Earth's surface surrounding the Equator and bounded by the Tropic of Cancer (23.4° N latitude) and the Tropic of Capricorn (23.4° S latitude). It is characterized by high annual precipitation and the absence of any significant seasonal variation in temperature. The term is often used more broadly to describe any area possessing what is considered a hot, humid climate.
- true north
- The direction along the Earth's surface towards the Geographic North Pole. Geodetic true north differs from magnetic north and grid north, and also very slightly from astronomical true north, which is based on the direction of the north celestial pole.
- tundra
- A treeless plain characteristic of the Arctic and subarctic regions.
- underpopulation
- Economically, a situation in which an increase in the size of the labor force will result in an increase in per-worker productivity.
- uniform region
- A territory with one or more features present throughout which are absent or unimportant elsewhere.
- Universal Transverse Mercator (UTM)
- upland
- Any area of land that is higher in elevation relative to another area, especially one that is populated by low hills or situated atop a plateau. The term is often used as a conditional descriptor to distinguish related habitats or ecosystems, especially freshwater riparian areas, on the basis of elevation above sea level. Upland areas are usually characterized by relatively fast-flowing waterways and hilly or rocky terrain. Contrast lowland.
- urban
- An adjective describing a settlement with a high population density and a developed infrastructure of built environment; places of this type are variously categorized as cities, towns, or conurbations, or simply called urban areas. Contrast suburban, exurban, and rural.
- urban geography
- The sub-discipline of geography that derives from the study of cities, urban processes, and the built environment.
- urban sprawl
- The unrestricted growth of housing, commercial development, and roads (typically of low densities) over large expanses of land, usually within or near an existing urban or suburban area and with little concern for civic planning. It is often considered a type of urbanization and almost always carries negative connotations.
- urban studies
- The study of the development of cities and urban areas, especially from historical, architectural, or civic planning perspectives.
- urbanization
- The process by which a human population shifts from rural to urban residency, the gradual increase in the proportion of people living in urban areas such as towns and cities, and the ways in which human societies respond and adapt to this change. Urbanization may be characterized as a specific condition at a set time (e.g. the proportion of the total population or physical area within a given set of towns or cities) or as an increase in that condition over time. It precipitates enormous social, economic, and environmental changes for the planet as a whole.
- vale
- Another name for a valley.
- valley
- 1. A low area between hills or mountains, often with a river running through it.
- 2. A depression that is longer than it is wide.
- vertical exaggeration
- A scale used in certain maps, such as raised-relief maps, that deliberately distorts the apparent elevation of the map's topography in order to emphasize vertical features, which might otherwise appear too small to identify relative to the corresponding horizontal scale.
- vent
- An opening at the Earth's surface through which volcanic materials (lava, tephra, and gases) erupt. Vents can be at a volcano's summit or on its slopes; they can be circular (craters) or linear (fissures).
- viewshed
- The geographical area that is visible from a particular location. It includes all surrounding points within line-of-sight of the location and excludes points beyond the horizon or obstructed by terrain and natural or artificial objects.
- village
- A small, clustered human settlement or community, usually larger than a hamlet but smaller than a town and often in rural areas, though the criteria for distinguishing a village can vary considerably in different parts of the world.
- virtual globe
- volcanic avalanche
- A large, chaotic mass of soil, rock, and volcanic debris moving swiftly down the slopes of a volcano. Volcanic avalanches can also occur without an eruption due to an earthquake, heavy rainfall, or unstable soil, rock, and volcanic debris.
- volcanic crater
- A type of crater created by volcanic activity, typically shaped like a bowl and containing one or more volcanic vents. Compare caldera.
- volcano
- A vent (opening) in the Earth's surface through which magma erupts, or the landform that is constructed by eruptive material.
- wadi
- 1. Another name for a valley, used primarily in Arabic-speaking parts of the world.
- 2. A dry, ephemeral riverbed which contains water only when heavy rainfall occurs.
- wash
- See arroyo.
- water gap
- A low point or opening in a ridge or mountain range carved by the erosional activity of flowing water and through which water continues to flow in the present day. Contrast wind gap.
- water mapping
- A collection of data represented as a map showing different aspects related to water supplies.
- water pollution
- The contamination of water by chemical or biological constituents which make it unfit for use.
- water table
- The level below the land surface at which the subsurface material is fully saturated with water. The depth of the water table reflects the minimum level to which wells must be drilled for water extraction.
- watercourse
- Any channel followed by a flowing body of water such as a river or stream, potentially including channels that are dry for part or all of the year.
- watershed
- Another name for a drainage divide or drainage basin.
- waterway
- Any body of water that is deep, wide, and slow enough to be navigable by watercraft.
- wave-cut platform
- A flat erosion surface along the shore of a lake, bay, or sea that is formed by the undercutting and eventual collapse of a sea cliff as a result of repetitive wave action.
- weathering
- The breaking of rocks into smaller rocks, gradually becoming soil.
- Western Hemisphere
- The half sphere of the Earth that is west of the Prime Meridian and east of the antimeridian. It is opposite the Eastern Hemisphere.
- wetland
- wilderness
- Any natural environment which has not been significantly developed or modified by human activity, or within which natural processes operate without human interference. Such areas are considered important for the survival of wild plant and animal species as well as for maintaining biodiversity and ecological stability. Wildernesses are often protected areas.
- wind gap
- windward
- The side of a landmass facing the direction from which the wind is blowing. Contrast leeward.
- world city
- See global city.
- World Geodetic System (WGS)
- A standard geographic coordinate system, spheroidal reference ellipsoid (for raw altitude data), and geoid (which defines the nominal sea level) used in cartography, geodesy, and satellite navigation applications worldwide. The latest revision, WGS84, is the standard coordinate system used by the Global Positioning System.
- world map
- A map of most or all of the surface of the Earth.
- yardang
- A streamlined protuberance carved from bedrock or any consolidated or semi-consolidated material by the dual action of wind abrasion and erosion, especially one found in a desert.
- zoning
- The public regulation of land and building use to control the character of a place.
- zenith
- The imaginary point on the celestial sphere that is directly above a particular location (i.e. in the vertical direction exactly opposite to the apparent direction of the gravitational force at that location). Contrast nadir.