Thisglossary of geography terms is a list of definitions of terms and concepts used ingeography and related fields, includingEarth science,oceanography,cartography, andhuman geography, as well as those describing spatial dimension, topographical features, natural resources, and the collection, analysis, and visualization of geographic data. It is split across two articles:
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 commonculture.
A governmental agency which manages, produces, and publishestopographic maps, geographic data, and sometimescadastral information that is specific to an individualnation or political territory, such as the United Kingdom'sOrdnance Survey.
A type ofprotected area created and managed as a public park by anational governmental authority forconservation purposes. Though individual governments designate national parks differently, they usually share the common goal of preserving natural or semi-natural landscapes (oftenwilderness) for posterity and as symbols of national pride.
A unit of distance traditionally defined as the length equal to oneminute of arc (1⁄60 of onedegree) along ameridian of the Earth. Because the Earth is not a perfect sphere, the length of one minute of arc at theEquator differs from that measured at thegeographic poles; thus the modern internationally agreed-upon standard defines the nautical mile as the average of these two extremes: 1,852metres (6,076feet; 1.151miles).[1] It is widely used in air, marine, and spacenavigation as well as for defining the limits ofterritorial waters.
1. (of a place) Capable of beingnavigated; sufficiently deep, wide, predictable, and/or free of obstructions to afford easy or safe passage to vessels such as ships or automobiles. The term is often used to describeriverchannels and coastalinlets.
2. (of a vessel) In a navigable condition; steerable; seaworthy or roadworthy.
Atide of decreasedtidal range occurring semi-monthly as a result of the Moon being inquadrature with respect to the Earth and the Sun (i.e. in the first quarter or last quarter phases, when roughly half of the lunar disk is visible), or the time period recurring every 14 days during which such tides occur. The average height of the high waters of the neap tides occurring at a particular location is calledneap high water orhigh water neaps, and that of the corresponding low waters is calledneap low water orlow water neaps.[2] Comparespring tide.
The part of abeach between theshoreline and the line at which the waves break.[2]
neatline
A line separating the main body of amap from the map's margin. On a standardquadrangle map, the neatlines are themeridians andparallels delimiting the quadrangle.[3]
neck
1. A narrow stretch of land with water on each side, e.g. anisthmus orpromontory.[4]
A geographically localizedcommunity within a largercity,town,suburb, orrural area, particularly one which supports considerable face-to-face interactions between residents.
A top-down view of the polar latitudes of Earth's Northern Hemisphere, centered on theGeographic North Pole and showing the distinct locations of the actualMagnetic North Pole and the idealizedGeomagnetic North Pole as of 2017. Only the Geographic Pole is in a stationary position; the Magnetic and Geomagnetic Poles are both gradually moving eastward.
A combination of a humansettlement and an area of cultivated vegetation in an otherwise desolatedesert or semi-desert environment, made fertile when sources offresh water, such as undergroundaquifers, irrigate the surface naturally or via man-made wells.
The approximate geometricshape of the Earth: a three-dimensional ellipsoid that is nearly but not exactly a true sphere, being instead slightly flattened at the poles and slightly elongated at the equator.
(of a stream, river, or any natural water flow) Flowing in the direction opposite to that of the dip of the underlying rock strata.[4] Contrastconsequent andsubsequent.
The vast, contiguous body ofsalt water covering more than 70% of the Earth's surface area and surrounding thecontinental 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.[6] TheInternational Hydrographic Organization recognizes five principal oceanic divisions on Earth: from largest to smallest, they are the Pacific Ocean, Atlantic Ocean, Indian Ocean,Southern Ocean, and Arctic Ocean.
The scientific study of the Earth'soceans and all processes and phenomena relating to them, including their formation and evolution over time; their physical and chemical properties and how these vary within the ocean and across its boundaries; their interactions withlandmasses alongcoasts; thebathymetry and geology of thesea floor;currents, waves, and geophysical fluid dynamics;marine life and ecosystems; and how humans affect and are affected by oceans. The interdisciplinary field draws from and involves a diverse range of other sciences, including physics, biology,geology,hydrology, meteorology, and climatology, among others.
Atoponym or proper name for a house or other residential building, or in the broadest sense for any inhabited settlement, such as a village, town, or city.[7]
One of a series of regularly spaced bands of alternating height and color visible on the surface of someglaciers, resulting from seasonal patterns ofalimentation andablation. Because ice flows faster near the center of the glacier, where there is less friction with the surroundingglacial bed, ogives are usually shaped into conspicuousarcs that point towards theterminus of the glacier.[8]
The part of theocean that is beyond or outside ofcoastal areas,[10] i.e. distant from land and not enclosed or partially enclosed by it. Inoceanography, the term is synonymous withpelagic zone and is often defined as all oceanic waters seaward of anycontinental shelf; politically and economically, "open ocean" usually refers to all areas of a sea or ocean that are not withinterritorial waters (hence, any area thatis withininternational waters) or, much more restrictively, not within any sovereign state'sexclusive economic zone. See alsohigh seas.
Anyvertical datum used by the BritishOrdnance Survey as the basis for reportingelevations onmaps. In modern Great Britain, the standard ordnance datum is the ODN, defined as themean sea level calculated from hourly observations of the tidal gauge at Newlyn, Cornwall, between 1915 and 1921. All heights shown on British maps are measured from thisbenchmark.[4]
orientation
The position of or the act of positioning a person or object with respect to the directional points of acompass, especially the placement of amap orsurveying instrument in the field so that a north–south line on the map or instrument liesparallel to a north–south line on the ground.[4] Determining one's orientation at a given time is the chief aim oforienteering, and is generally of critical importance innavigation.
The use of amap andcompass tonavigate over unfamiliar terrain, either by land or water; or a recreational activity or competitive sport in which participants navigate in this way, generally on foot from point to point along a predeterminedroute, and often inwilderness areas while racing to complete the course within a certain period of time or before competitors.
An aerial photograph or satellite image that has been geometrically corrected ororthorectified such that thescale is uniform across all parts of the image, allowing the image to align with a particularmap projection. In an uncorrected aerial photo, distances on the ground may be distorted bytopographic relief, camera tilt, or the curvature of the Earth; techniques of digital image processing can compensate for these distortions, often by combining multiple images captured from slightly different perspectives into a single composite image. Orthophotos can be used to measure true distances because they accurately depict the relative sizes and positions of features on the Earth's surface.
Any visible exposure ofbedrock or ancientsuperficial deposits on the surface of the Earth; or more generally, any bare, rocky surface that is topographically distinct from the surroundingterrain. 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.
1. Alluvial sediment, usually consisting of fine sand, silt, and clay, that has beendeposited on thefloodplain of a river or stream by flood waters that have broken through or overtopped the river'sbanks.
2. Thestage when a river or stream overflows the banks of its normal channel and spreads on to a floodplain, depositing such sediment.
An elliptical dome-likepermafrost mound containing alternating layers of ice lenses andpeat or mineral soil, commonly 3–10 metres (10–33 ft) high and 2–25 metres (7–82 ft) long, and occurring frequently inbogs in theArctic and subarctic zones of discontinuous permafrost.[11]
Any shallow, generally roundedbasin or hollow, which may seasonally capture and hold water from rainfall or snowmelt, especially one occurring in an arid or semi-arid region; more specifically, the flat central part of such adepression, which may be temporarily or seasonally flooded.[4]
A rounded or circulardepression 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 withpothole, though the latter may also refer to distinct geological features.
An instrument that enables the mechanical copying of amap or technical drawing on a selectable scale, such that the movement of one pen, in tracing an image, produces identical movements in a second pen, resulting in a duplicate image that is the same size, enlarged, or miniaturized with respect to the original. Pantographs typically consist of hinged rods arranged in the shape of a parallelogram which rotate about a fixed point.[4]
parallel
1. (geometry) Extending in the same direction, equidistant at all points, and never converging or diverging; having the same orientation, nature, tendency, or course; corresponding or similar.
Aglacier with low rates of bothalimentation andablation because it receives only light snowfall and undergoes little melting throughout the year. Such glaciers move very slowly and transport relatively small amounts of ice and debris.[4] Contrastactive glacier.
Any land used forgrazing by livestock, often a naturalgrassland supporting native grasses and forbs with little or no active management by humans, as opposed to ameadow, where the vegetation is mown for hay orsilage.[4]
1. A pointed or protruding top or other vertical projection on a landform, e.g. amountain, especially implying the highest point or elevational maximum, i.e. thesummit.[4]
2. A mountain as a whole, in particular a high,isolated, orprominent one.
pediment
An eroded, often bare rock platform, cut into the localbedrock, usually slightly concave and triangular in shape and extending over a considerable area at the foot of an abrupt mountainslope or face, the lower edge sloping gently away. Pediments form basal slopes of transport forweathered material derived from the steeper slope above, and are characteristic of arid and semi-arid lands.[4]
The scientific study of the morphology, composition, and spatial distribution of soils, with an emphasis on classifying soils and understanding their formation and evolution.[4]
The uppermost layer of the Earth'scrust that is composed of soils and subject topedological processes such as soil formation and erosion, a consequence of dynamic interactions between thelithosphere,atmosphere,hydrosphere, andbiosphere.
A low-reliefplain leveled by long-term erosion, often implying a landscape that is in the final stages offluvial erosion during an extended period of tectonic stability, i.e. approaching the point at which all initial topographic inequalities such as mountains and hills have been eroded and evenly redistributed into a broad, flat, uniform surface at or near sea level.
A piece of land surrounded by water along the majority of its border while still being connected to amainland from which it projects.
perceptual region
An area of the Earth's surface that is defined by the perceptions of the people living there or by those of the general society, and thus is based largely on subjective or qualitative distinctions.
Astream that normally flows continuously throughout the entire year, without drying up, as opposed to a transient orintermittent stream.
pericline
Alsocentrocline.
Ananticline in which the rock strata have been arched up in the shape of a dome, such that the beds dip away on all sides from a higher central point.[4]
1. Of or relating to an area located adjacent to or on the margin of anice sheet orglacier, either presently or in the past, or to associated glacial or cryological phenomena.[4]
2. Describing any place where seasonal cycles of freezing and thawing modify the landscape in a significant manner.
A historical manuscript listing theports, safeanchorages, and coastallandmarks that a maritime vessel could expect to encounter along ashore orcoastline, arranged in order according to a particular direction of travel and including the intervening distances between them. See alsoitinerarium.
The uppermost layer of abody of water (e.g. alake orocean), defined by the maximum depth to which sunlight can penetrate thewater column. The photic zone usually supports large populations of photosynthetic organisms and the majority of the aquatic life inhabiting the body as a whole.
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.
Aperiglacial landform consisting of a relatively large conical mound of soil-covered ice, commonly 30–50 metres (100–160 ft) high and up to 1,000 metres (0.6 mi) in diameter, and that grows and persists in part as a result of hydrostatic pressure within and below thepermafrost ofArctic and subarctic regions.[11]
Any natural, free-standing, vertical or nearly vertical column of earth or rock in the shape of a tall, often slender shaft or spire, and which is distinguished by its isolation from nearby rocks or other landforms. The term is applied to a wide variety of geological formations of various sizes and has numerous regional and local synonyms with which it may be used more or less interchangeably. See alsodemoiselle,hoodoo,prominence,stack, andzeuge.
Rockspires or pinnacles may range in size from small pillars a few metres tall to entire mountains stretching thousands of metres from base to summit. Left: Large Flowerpot onFlowerpot Island, Ontario, Canada; 12 metres (39 ft). Right: Southeast face ofCerro Torre, border of Chile and Argentina; 2,100 metres (6,900 ft).
A type ofcrater formed by thesinking or collapse of the surface lying above a void or empty chamber. Pit craters are similar tocalderas and are often associated with volcanic activity, but lack theejecta deposits andlava flows ofvolcanic craters.
A particular point on the Earth's surface, or the area surrounding such a point, having or encompassing a definiteposition; alocation, often specifically named, that is identifiable in social interaction because humans have endowed it with meaning or purpose;[13] amental representation of a physical space created from functional or emotional associations in the human mind. The concept of place – how places are created, identified, mapped, connected, and used – is fundamental to many aspects ofgeography.
The measure of approval or satisfaction accorded by an individual to alocation in his or heraction space; the value or usefulness of a particular place as perceived by a particular person. Dissatisfaction with place utility may result inmigration.[4]
1. (mineral deposit) An accumulation of valuable minerals, particularly gold, formed by gravity separation from a source rock during natural sedimentary processes. The minerals,weathered from rocks or veins, are washed out by streams and mixed withalluvial deposits of sand or gravel, from which they can then be extracted byplacer mining.
2. (reef) A flat, shallowsandbank orreef submerged beneath the ocean surface, often with a sandy bottom suitable as ananchorage for seagoing vessels.
A small drawing board mounted on a tripod used insurveying, site mapping, and related disciplines to provide a solid and level surface upon which to make drawings, charts, and maps while in the field.
planimetric map
A map which uses a two-dimensionalcoordinate system, i.e. in which each point is represented by only two coordinates (x,y), as if all of the depicted features existed within a single, flat plane. These maps usually exclude information aboutvertical position and therefore do not showtopographic relief and represent only horizontal distances.[14]
Acadastral map, drawn to scale, showing the legal boundaries and divisions of asurveyed tract of land, particularly of the type used to divide real property for sale and settlement in thePublic Land Survey System of the United States.[14]
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 calledtectonic plates.[5]
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.
An exceptionally flat, aridbasin that is the drybed of an evaporatedlake; or the shallow, usually saline lake itself which periodically forms when the basin is temporarily covered with water, e.g. after substantial rainfall. See alsosalt pan.
An erosional phenomenon whereby aglacier gradually scours and displaces pieces of rock from thebedrock beneath it and transports them along with the glacial flow of ice and debris. As the glacier moves down avalley, friction causes the basal ice to melt and infiltrate joints and cracks in the bedrock; repeated freezing and thawing widens and deepens these cracks, eventually loosening the rock and causing large blocks and boulders to be carried along by the overlying ice. These boulders are often deposited hundreds of kilometers from their source, becomingerratics. The term is also sometimes used to describe the similar process ofquarrying, which occurs on a smaller scale in fast-movingrivers andstreams.[4]
A vertical reference line created by suspending a weight, known as aplumb bob orplummet, from a string above the Earth's surface and allowing it to hang freely in the direction of the pull of gravity. A precursor to thespirit level, plumb lines are used to establish a verticaldatum in a wide range of applications, particularly insurveying to determine thenadir of a point in space, and often in combination with an instrument to set the instrument precisely over a fixedsurvey marker.
A deepdepression at the base of awaterfall into which the water drops with great force,plucking andabrading the rock beneath and behind the falls and creating an often nearly circular concavity which may remain filled with water long after the waterfall itself dries up.[4]
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 trueice caps and are more correctly termedice sheets.
Either of the two high-latitude regions surrounding the Earth's geographical poles (theNorth andSouth Poles), which are characterized by frigid climates and extensivepolar ice caps. The polar region of the Northern Hemisphere is often simply called theArctic and that of the Southern Hemisphere is called theAntarctic.
A low-lying tract of land enclosed bydikes, forming an artificial hydrological entity by creating land from a naturally inundated area, e.g. byreclaiming land from a lake or sea, or by building barriers around afloodplain ormarsh and then draining it. All polders are eventually below the surroundingwater table some or all of the time, making them especially prone to flooding, and they often require continuous draining.
pole
1. An extreme geographical point, especially one of a pair.
A location that, with respect to a given geographical criterion, is the most difficult to reach according to that criterion, e.g. the geographical location that is the most distant from the nearest point meeting that criterion. The term most commonly refers to the so-called continental or oceanic poles of inaccessibility, i.e. the point on a given continental landmass that is the furthest distance from a coastline, and the point in the ocean that is the furthest distance from land, respectively.
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 ofhuman geography, its primary concerns can be summarized as the relationships between people, state, and territory.
A very largeplain found inkarstic regions, enclosed within adepression, usually elliptical, with a flatfloor either of bare limestone or covered byalluvium, and generally surrounded by steep limestone walls; or more broadly any enclosed or nearly enclosedvalley. The term is used primarily in the Slavic-speaking world.
An area of unfrozen seawater surrounded by an otherwise contiguous area ofpack ice orfast ice. Polynyas are often formed along polar coastlines through the action ofkatabatic winds, but may also form in theopen ocean.
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 acity,town,region,country, or the entireworld.
A branch ofhuman geography that studies the ways in which spatial variations in the composition, distribution, migration, and growth ofpopulations 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 thedemographic processes offertility,mortality, andmigration.
positional error
The amount by which the mapped location of an imaged cartographic feature fails to agree with the feature's actual location in the real world.[2]
Any technology or mechanism used to determine theposition of an object in space. Numerous methods for determining position have been practiced since ancient times, though modern positioning systems generally rely on electromagnetic and/orsatellite-based technologies capable of providing coverage ranging fromlocal or regional toglobal and accuracy ranging from tens of metres to sub-millimetre.
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.[5]
The branch ofhydrology that studiesrivers, including the processes and phenomena that occur at theirsources,main channels, andmouths; the structure and morphology ofdrainage basins; and the water, thermal, ice, and sediment regimes that affect and are affected by riverdischarge.
1. Any smooth, bowl-shaped or cylindrical hollow, generally deeper than it is wide, that is carved into the rockybed of awatercourse such as astream orriver. 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 toplunge pools beneathwaterfalls, which are created by similar processes. See alsokolk.
2. A vertical or steeply inclinedkarstic shaft in alimestone deposit.
3. In theGreat Plains of North America, a shallowdepression, generally less than 10 acres (4.0 ha) in area, occurring betweendunes or onmorainic relief on aprairie and often filled by an intermittentpond ormarsh.
A type of temperategrassland 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.
Apeninsula connected to themainland by an extremely narrowneck of land such that the land at its distal end is very close to being anisland. See alsotied island.
The imaginary line running from north to south through theRoyal Observatory inGreenwich, England which is assigned alongitude of 0 degrees and is therefore used as the reference point for all other lines of longitude.[6]
The natural extension of ashoreline into a body of water by the gradual accumulation of sediment over time,[15] especially as a result offluvialsedimentation processes, such as the protrusion of ariver delta into the sea. This occurs when the volume of sediment carried by the river and deposited at its mouth exceeds the volume lost throughsubsidence, sea level rise, or coastal erosion.
prominence
1. A conspicuous high point that projects above or beyond its surroundings, e.g. abutte or apromontory.[9]
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.
The study of specific effects of the geographical environment on the emotions and behaviors of individuals, whether consciously organized or not; the landscape of atmospheres, histories, attitudes, actions, and characters that occupy environments and influence group and individual psychologies.
Any land area held and managed in thepublic domain by a federal or local government for use by the general public, as opposed to privately held land, for which access and use can be restricted by the individual landholder.
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.[5]
pull factor
In human geography, anything that encourages people to move orimmigrate to a new place or location.
Anecoregion in the central Andes Mountains of South America, or any of the various high-altitude ecosystems encompassing it, including colddeserts and alpinegrasslands.
push factor
In human geography, anything that encourages people to leave oremigrate from a place or location.
A standard division of the Earth's surface area used inmaps produced by theUnited States Geological Survey. Quadrangles are four-sided polygons of varying size, depending on themap series; for example, 7.5-minute quadrangles divide the mapped surface into quadrilaterals measuring 7.5 minutes (0.125degrees) oflatitude by 7.5 minutes oflongitude, with each 7.5-minute map showing thetopographical 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.
A place from which stone, rock, sand, gravel, slate, oraggregate is excavated from the ground, especially a large man-madepit that is exposed to the open air.
quaternary sector (economic activities)
Activities focused on the management, processing, and research of information.
The distance between the two rails of a railroad.[5]
railroad bed
The track or trace of a railroad route, commonly raised slightly above the adjacent natural ground surface and constructed mostly of locally occurring, earthy materials (e.g. gravel and rock fragments).[11]
An area on theleeward (downwind) side of a mountain or mountain range that receives greatly diminished precipitation.[5]
Arain shadow is created when a mountain range forces moist air masses upward, causing them to condense in the upper atmosphere and precipitate all of their moisture, which leaves them relatively dry by the time they reach the other side of the range.
Anyforest characterized by abundant rainfall, dense layers of vegetation, and extremely highbiodiversity. Rainforests are found in both tropical and temperate regions. The termjungle is sometimes used to refer to a tropical rainforest.
rake
A slopingterrace on a mountainside or rock face. The term is used primarily in Scotland.[4]
A section of ariver orstream where theriverbed is sufficiently steep, the rate of flow is sufficiently fast, and/or thechannel is sufficiently narrow or obstructed by shallow or protruding rocks or other obstacles that the water at the surface is visibly swift, turbulent, and broken,[4] often forming large white-cappedbreaking waves,eddies,whirlpools, and "holes", in contrast to other sections where relatively slow, steady, laminar flows predominate. Rapids can persist long enough to form distinct, stable patterns at particular locations, though they are ultimately dependent on water volume and thus may change seasonally, disappearing entirely if water levels are too low or too high. Generally, watercourses are more likely to form rapids closer to theirsource, where channels are relatively shallow and narrow and often pass through mountainous or highly eroded terrain, than to downstream portions near theirmouth, where channels tend to be deeper and wider.
A representation of spatial data within a two-dimensional image that defines space as a rectangular array or grid of equally sized cells arranged in rows and columns, where each cell can be identified withlocation coordinates and is associated withattribute values containing a discrete amount of information from one or more layers or "bands". Raster models are useful for storing and presenting large amounts of complex multivariate data that vary continuously across space, as is commonly encountered inmaps, aerial photographs, satellite imagery, and many other aspects ofgeographic information science. Raster data are contrasted withvector data, which instead store and represent geographic information in the form of points, lines, and polygons.[14]
Afluvial slope landform of relatively steep sides, sometimes with an intermittentstream flowing along the downslope channel. Ravines are typically narrower and shallower thancanyons, larger thangullies, and smaller thanvalleys.
1. A relatively straight, level, uninterrupted segment of astream,river,channel, or otherwatercourse, or of anarm of a sea or ocean, traditionally defined by its ability to be sailed in one "reach" (i.e. on a singlepoint of sail, withouttacking) and also usually implying a line-of-sight stretch of water between two bends or horizons, or betweenrapids,locks,stream gauges, or any otherlandmarks.
2. Any expanse or widening of a watercourse, natural or man-made (commonly on dammed streams and rivers), or even an expanse of land, especially one that appears to be visually contiguous.
3. Influvialhydrology, a length of a stream or river having fairly uniform characteristics and which is therefore convenient to study as a discrete subdivision of the longer whole.
1. Any land area that is artificially created from earthy fill material that has been intentionally placed and shaped so as to approximate natural contours, especially as part ofland reclamation efforts such as those designed to burytailings following the cessation of mining operations.
2. An area of land, commonly submerged underwater in its natural state, that has been protected by artificial structures such asdikes and drained for agricultural or other purposes (e.g. apolder).[11]
A submergedridge-like ormound-like structure built by sedentary calcareous organisms, especiallycorals, 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 thesea floor, rising to or nearly to the water's surface.[11]
A mathematically defined surface that approximates thegeoid for use inspatial reference systems orgeodetic datum definitions. Because of their relative simplicity, reference ellipsoids are used in geographic applications as preferred surfaces on whichgeodetic network computations are performed and point coordinates such aslatitude,longitude, andelevation are defined.
An area having some characteristic or characteristics that distinguish it from other areas; aterritory that is of interest to people, for which one or more distinctive traits (e.g. climate, economy, history, etc.) define its identity.[5]
1. The feeling or expression of a common sense of identity, purpose, or group consciousness associated with a particular geographicalregion, e.g. the Southern United States,Scandinavia, orLower Egypt, often combined with the creation of institutions that accommodate that particular identity and shape public action.[4]
2. A movement to decentralize central government, placing administrative responsibility instead at a level intermediate between that of thestate and that of smaller local ormunicipal units.[4]
3. In architecture, an approach that strives to counter placelessness and lack of identity by incorporating elements of the building's geographical context in its design.
4. In linguistics, a word or phrase originating in, characteristic of, or limited in usage to a particular region.
Acity located outside the core of ametropolitan area that serves as an independent driving force for political, economic, or cultural development within a largerregion. Contrastmetropolis.
Theelevation oraltitude of one location relative to another location; the difference between the highest and lowest points within a given geographical area.[4]
A range of social-cultural systems including designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relate humanity to supernatural, transcendental, and spiritual elements.
(of a particular location) Isolated or inaccessible, either by being physically very distant from another location or by lacking connectivity to transportation or communication networks which would otherwise make exchange between locations convenient.
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.
The fraction expressing the ratio between the distance measured between two points on amap and the corresponding actual distance measured between those points in the real world, used to indicate the map'sscale. The fraction's numerator is typically 1 (indicating one of some specified unit of length, e.g. inches or centimetres) and the denominator is the number of the same unit in the real world which this length represents on the map. For example, a representative fraction of1⁄1,000,000, often written as1:1,000,000 or1:1 mn, means that one inch (or one centimetre) on the map itself is equivalent to one million inches (or centimetres) in the real world. Onestatute mile is equal to 63,360 inches, so 1,000,000 inches is approximately 16 miles.[4]
reservoir
Alsoimpoundment.
An artificiallake or an artificially enlarged natural lake that is used to store water. Reservoirs are often created by the construction of adam orlock in a naturaldrainage basin.
A line drawn on the surface of a sphere (or on an idealized representation of the Earth) which crosses allmeridians oflongitude at the same angle, and which therefore has constantbearing relative totrue ormagnetic north.
Arhumb line or loxodrome spirals toward the north pole of a sphere, crossing all lines of longitude at the same angle.
Thebuild-up of residential and economic communities along the main routes of communication and transportation radiating from acity or other developed area, because of the advantages of accessibility, relatively inexpensive land, and trade from passers-by.[16]
An elongated raised landform which forms a continuous elevated crest for some distance, such as a chain ofhills ormountains. The line formed by the highest points, with only lower terrain immediately to either side, is called theridgeline.
A shallow water channel, generally not more than 6 inches (15 cm) deep, that has been cut into a soil surface (especially a cultivated agricultural soil) by the erosive action of flowing water. Larger erosional channels may be calledgullies.
The area along the margins orbanks of ariver,stream,canal,estuary, or otherwatercourse; or the interface between land and a watercourse, generally including any land that is close enough to the watercourse to be frequently or persistently hydrated with its water. Riparian areas are importantbiomes with characteristics of both terrestrial and aquatic ecosystems, and often support dense hydrophilic plant communities of highbiodiversity. They often overlap with and by some definitions may be consideredwetlands.
An area of land enclosed within the bend of ariver, especially where the bend is extended or pronounced (e.g. ameander) and the only road access is along theisthmus. The term is used primarily in Australia.
Anymap that shows the man-made roads, streets, highways, railways, and/or other transportation routes within a specific coverage area, especially one which prioritizes the display of this information over other information such as natural features. Road maps are designed to emphasize information relevant to motorists, often includingpolitical boundaries and labels as well aspoints of interest such as important buildings and businesses, tourist attractions, parks and recreational facilities, hotels, restaurants, gas stations, public transit networks (airports, train stations, etc.), and emergency services. The widths of the roads themselves are often exaggerated to make the routes more conspicuous.
A diagram printed on amap consisting of a set of lines radiating from a point and marked so as to indicate velocity or some other quantity havingdirection; e.g. acompass rose orcurrent rose.[2]
1. A way or course taken in getting from one place to another; an established or selected course of travel or action; a line of travel or means of access, especially when marked by a path, track, road, or rail.
2. A circuit traveled in delivering, selling, or collecting goods, e.g. by a mail carrier.
routefinding
The determination of a viableroute or line of travel between two places, especially in rugged or unexplored areas such as mountainous terrain or in conditions of poor visibility, and especially when done without the benefits of prior knowledge of the area, maps, or other technology that might aidorienteering, instead relying entirely on recognition of natural features andlandmarks and quick estimations of distance, scale, ease, and safety.
rural
An adjective describing any geographic area located outside areas of significant human population such astowns andcities; all population, housing, and territory not included within anurban area is often said to be rural. Rural areas are typified by lowpopulation densities, very smallsettlements, and expansive areas of agricultural land orwilderness.
Amudflat or sandflat in thesupratidal zone of an arid or semiaridcoastal plain in which large amounts of mineral salts accumulate; or, more generally, any flat area, coastal or interior, where salts or other evaporites readily precipitate at or near the land surface.[18] The term is used primarily in Western Asia and Africa, though the landforms it describes occur worldwide. See alsosalt pan,salt marsh, andplaya.
For a given pair ofmountain summits, the region surrounding theelevational low point orcol on theridge connecting the two summits; mathematically, it is thecritical point that is simultaneously a relative minimum in one axial direction (e.g. between the peaks) and a relative maximum in the perpendicular direction. Assuming it is navigable, a saddle can be thought of as the area surrounding the highest point on the lowest route which one could use topass between the two summits.
Thesaddle is the highest point of the pass between the two mountains.
A naturalcoastalmarsh ecosystem in the upperintertidal zone, between land and openseawater orbrackish water, that is regularly flooded by thetide at high water. Salt marshes support dense stands of terrestrial salt-tolerant plants, especially grasses and low shrubs, which trap and bind sediments from the ocean and help protect the nearbyshoreline from coastal erosion.
A large, flat expanse of land naturally covered with mineral salts and/or otherevaporites, usually to the exclusion of virtually all vegetation. Salt pans are common indeserts, where they form by the precipitation of dissolved mineral solids as a large body of water evaporates. See alsoplaya.
Any naturally occurring water, especially the water from asea orocean, characterized by high concentrations (between 3 and 5% by volume) of dissolved salts, primarilysodium andchloride ions, relative tofresh water orbrackish 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.
A flat area where the soil or ground surface is covered with or composed of sand that has been transported from elsewhere anddeposited by wind or oceans, rather than by weathering of the localbedrock.
A method ofnavigation or an autonomous geospatialpositioning system that relies on artificialsatellites in orbit around the Earth to transmit time signals at radio frequencies along aline of sight to electronic receivers on the surface, which can then use this information to determine the receiver's location, direction, and the current local time to high precision. Satnav systems operate independently of telephonic or internet connectivity, though simultaneous use of these technologies can enhance the accuracy and usefulness of the positioning information generated.
A formally independentstate or polity which nevertheless depends economically, politically, or militarily upon, or is strongly influenced or controlled by, another, more powerful state.[4]
A mixedwoodland-grassland ecosystem characterized by scattered trees and bushes that are sufficiently widely spaced that the canopy does not close, permitting enough sunlight to reach the ground to support an unbroken herbaceous layer of primarily xerophytic grasses. The term is used especially to refer to the vast, hot, arid grasslands covering parts of equatorial Africa, South America, and northern Australia, but is also sometimes applied more broadly.[4]
A steepcliff face or slope terminating an elevated surface of lowrelief,[4] formed either because of faulting or by the erosion of inclined rock strata.[5]
1. A narrow stretch offloodplain added to the outer end and downstream side ofspurs between enclosedmeanders on a river.[4]
2. A type ofpoint bar consisting of a low, narrowridge running in line with the curve of a meander, formed when the river overflows itsbanks.[4]
sea
1. Any large body ofsalt water surrounded in whole or in part by land.
2. Any large subdivision of theWorld Ocean. "The sea" is the colloquial term for the entire interconnected system of salty bodies of water, includingoceans, that covers the Earth.
A navigable route across a wide waterway such as anocean,sea, or largelake that is regularly used for maritime trade by large vessels or ships because it is safe, direct, and economical.
The average level of the surface of one or more of Earth'soceans from which heights such aselevation andaltitude are commonly measured. Often calledmean sea level (MSL), it is a type of standardizedgeodeticvertical datum that is used in numerous applications, includingsurveying,cartography, andnavigation. Mean sea level is commonly defined as the midpoint between the mean low and mean hightides at a particular location.[6]
Inhuman geography, the locations within an area where an individual or group searches for the resources necessary to meet their specific needs (e.g. for housing or employment), based on information from their currentawareness space.[4]
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.[5]
secondary-intercardinal directions
The set of eight intermediate directions used incartography andnavigation, each of which is located halfway between a pair ofintercardinal 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 acompass rose.
That portion of a region's economy devoted to the processing of basic materials extracted by theprimary sector; i.e. to the production of material goods.[5]
The principle on which political claims to territory in thepolar 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 particularlatitude. Because of the limited accessibility and generally low material value of both theArctic andAntarctic, the sector principle has emerged as a means of formally sharing responsibility for these regions between the world's sovereign states.[13]
sector theory
Alsosector model.
The view that commercial, industrial, and especially residential areas in acity develop in 'sectors' ordistricts along lines of transport and communication, from thecentral business district outwards. In manyurban areas the basic pattern of development often approximately follows this model, with industrial sectors developing along canals and railways, working-class housing developing near industrial sectors, and higher quality housing being built away from industrial zones but still in places with quick and convenient road access to other sectors.[19]
Either the intrinsic character of aplace or the meaning people give to it, or a mixture of both. This sense of meaning may include national, regional, or localidentity orawareness, or emotional attachments formed between humans and the places they reside in or travel to. It is often the intangible characteristics of a particular place which are most important to mental representations of that place; these characteristics may be natural and unintentional, or may be consciously created or preserved through memorable or singular structures in order to give a place a distinctive identity.[19]
A large block or pillar ofglacial ice formed by the intersection of numerouscrevasses where the glacier fragments as it reaches a steep slope. Seracs are usually found inicefalls, often in large numbers, in mountainous terrain.
The spatial distribution of where humans inhabit the Earth.
shadow effect
The phenomenon by which a large, well-servedurban center affects the transport services of a nearby smaller town or city, often by drawing producers and consumers away from the smaller settlement and toward the larger one, causing the smaller settlement to be relatively ill-provided with direct services.[4]
A rock formation created by the passage of aglacier over underlyingbedrock, which often results in asymmetrical erosional forms created byabrasion on the upstream side of the rock andplucking on the downstream side.
A broad area of very old rocks above sea level that is usually characterized by thin, poor soils and low population densities.[5]
Shields—large areas of the Earth's crust which are relatively inactive tectonically (here depicted in orange)—are found in the interior of every continental plate.
A natural submergedridge,bank, orbar that consists of or is covered by sand or other unconsolidated material and rises from thebed of abody of water to just below or above the surface.
1. A roundedspur on a mountainside; or abench on the side of aglacier-deepenedU-shaped valley, demarcating an abrupt transition between the gentle upper slopes which have been largely unaffected by glacial erosion and the steep lower slopes of the heavily eroded inner valley.[4]
2. The part of a roadway between the edge of the graded or paved driving surface and the top of theforeslope of an adjacent ditch or embankment.[2]
The features of aplace related to the immediate environment in which the place is located (e.g.terrain, soil, subsurface, geology,groundwater, etc.).[5]
situation
The features of a place related to its location relative to other places (e.g., accessibility, hinterland quality).[5]
A small, rockyislet orreef, often one of a series lying just offshore and parallel to the main trend of thecoastline, over which large waves may break at high tide or in stormy weather.[4]
An isolated mountain, mountain range, or high plateau characterized by conspicuous elevational gradients in geology, climate, and/or biodiversity, so that environments and ecosystems near the summit differ greatly from those of the adjacent slopes or the surrounding lowlands. This effectively cuts off the ecosystems of the highest areas, turning them into "islands" in a "sea" of dissimilar landscapes.
The brief period of time during which abody of water susceptible totides is completely unstressed because the tidal stream is almost still, i.e. there is no movementby conspicuous elevational gradients in either direction in the tidal current, usually the period immediately before and after thehigh andlow water marks, prior to the tide reversing direction.
Theline-of-sight distance along the relative direction between two points, especially two points which are not at the sameelevation relative to a specificdatum. If the two points are at the same elevation, the slant range equals the horizontal distance.[20]
slash
1. In the southeastern United States, a low-lyingswampy orboggy area, overgrown with shrubs and cane grasses and favorable for the growth of theslash pine and related trees.[4]
1. A 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 alandslide oravalanche.
2. The mass of material moved or deposited by such an event, and which has become fixed or settled upon the landscape.[11]
Cross-section of ameandering river: uneven currents result in asymmetrical channels with a gently sloping depositional bank, known as aslip-off slope, on the inside of each bend and a steep erosional bank, known as acut bank, on the opposite side.
The upward or downward inclination of a natural or artificial surface (e.g. a hillside or a road), or the degree or nature of such an incline; a deviation from the perpendicular or horizontal direction (these directions generally being assigned with respect to the direction of the force of gravity).[4] See alsograde.
A type ofwetland – usually aswamp, a shallowlake, or abackwater branching from or feeding into ariver – in which water tends to be stagnant or flows only very slowly on a seasonal basis.
A residential settlement orneighborhood, usually in or near anurban area, characterized by densely packed and poorly built or dilapidated housing units such as shacks and a deterioration or lack of civic infrastructure such as reliable water, electricity, sanitation, law enforcement, and other basic services, and usually associated with extreme poverty and overpopulation.[4]
The lowermost margin or extremity of aglacier, always either gradually advancing or retreating, sometimes partially hidden bymorainic material, and commonly featuring acave from which meltwater flows.[4]
The lowest elevation at which snow remains throughout the year if the summer warmth does not completely melt the winter accumulation, e.g. on a highmountain. This elevation varies widely withlatitude, local climate, directionalaspect, and steepness ofslope, such that the snowline may be very different on different mountains in the samerange, on different faces of the same mountain, or on the same face in different years.[12]
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 insolution by water. See alsoleaching.[5]
1. Any of the wide variety of formal techniques used to study entities according to their topological, geometric, or geographic properties.
2. An approach to geography in which the locational variations of a phenomenon or a series of phenomena are studied and the factors influencing or governing the observed patterns of distribution within space are investigated. This approach attempts to break down spatial patterns into simple elements so that measurements can be made of individual sub-patterns, which then allows the comparison of two or more distinct patterns and the development of statistical tests to determine whether a given pattern differs significantly from random variation.
The participation of individuals and groups of laypeople in decision-making aboutspatial planning andsocial rules in public spaces through the reflexive production and use of geographic media such asmaps,virtual globes, andGIS software, particularly 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.[5]
spatial diffusion
The process by which materials, ideas, diseases, or information are distributed or spread through space.
spatial interaction
Movement or exchange between locationally separate places.[5]
Acoordinate-based local, regional, or global system used to locate geographical entities and which defines a specificmap projection as well as transformations between different systems.
Amap that is not merely a diagrammatic representation of a place but is based on an aerialorthophotograph, such that the map includes actual imagery of ground-level features typically omitted from standard maps. Often, spatiomaps are created simply by overlaying annotations directly upon an orthophoto, such as a north arrow orcompass rose, ascale bar, political boundaries and labels, or other cartographical information. Spatiomaps are useful when reliable data from ground-basedsurveys are missing for a particular geographical area or when accurate maps must be produced very quickly, especially during disaster relief efforts where a natural disaster has dramatically changed ground-level detail but new surveys have not yet been conducted.
A type ofbar orshoal extending from abeach into anocean orlake and which develops by thedeposition of sediment as a result oflongshore drift. Spits form where the direction of theshoreline sharply changes direction, such as at aheadland, and often develop a "hooked" or recurve shape at their distal ends.
A lateralridge or other salient landform protruding from the side of ahill,mountain, or the main crest of aridge and typically surrounded on at least three sides by steep hillsides.
Acoastal landform consisting of a steep and often vertical column or columns of rock above the surface of the sea and formed by erosion due towave action. See alsopinnacle.
Inhydrology, the height of the surface of astream orriver at a particular location and a particular point in time, with respect to a reference height such as itsbed or a position on itsbanks, and used especially to monitor seasonal changes in discharge and flooding.[4]
stand
An area of vegetation dominated by a single plant species, e.g. a stand ofoak trees.[13]
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.[5]
A compulsory political organization with a centralized government that maintains a monopoly of the legitimate use of force within a certain geographical territory. Seecountry.
A steepmountainside,hillside, orescarpment, especially one with an averageincline between 30 and 60 degrees from the horizontal. The term is used primarily in the German-speaking world.
An adjective describing the side of ahill orridge that faces the direction from which an advancingglacier orice sheet is moving or has moved; i.e. facing upstream or "up-ice" with respect to the glacier, and therefore most exposed to its abrasive action. The opposite side, facing downstream or away from the glacier, is known as thelee.[11]
Abeach orshoreline, especially a former or relict one, now elevated above the present water level, which appears as a bench or other visible demarcation lining the length of the shore at a common elevation.[11] See alsohigh water mark.
The hierarchical classification of all of the branchingstreams comprising a river system orwatershed, usually by assigning an ordinal number to each individualtributary indicating the magnitude of itschannel and/or its position within the overall drainage sequence. Several different numbering methods are in common usage. In the Strahler system, the outermost tributaries (i.e. near thesources) are designated first-order streams, and at least two streams of any given order must combine to form a stream of the next higher order, e.g. two first-order streams unite to form a second-order stream, two-second-order streams join to form a third-order stream, and so on until the largest channel ormain stem, terminating at themouth, is reached.[4]
The Strahlerstream order system for assigning numbers to streams
The bottom of thechannel of astream orriver, 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 thebank is the part above the water line.
strip map
Amap covering only a narrow band of territory in which the user is interested, e.g. alongside each side of a trail or vehicle route.
A largelandmass forming a contiguous part of an even largercontinent, though often separable by physiographic or political boundaries, e.g. theIndian subcontinent; or a non-contiguous but still very large landmass that is smaller than one usually termed a continent, e.g.Greenland.
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.[12]
2. Of or relating to the deepest parts of alake or other large body of freshwater, distant from theshore, where plants cannot root.[15] See alsoaphotic zone.
(of a stream, river, or any natural water flow) Flowing along acourse determined by the structure of the localbedrock.[4] Contrastconsequent andobsequent.
An adjective describing a mixed-use or residential area existing either as an ancillary part of anurban area or as a separate community withincommuting distance of acity; a place of this type is called asuburb. Suburbs are often defined by commuter infrastructures and have lower population densities than inner-cityneighborhoods.
suburbanization
The process by which a humanpopulation shifts fromurban tosuburban 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 tourbanization.
A point on a surface that is higher inelevation than all points immediately adjacent to it. Mathematically, it is a local maximum in elevation. The highest point of ahill ormountain is often referred to as the summit.
The area along ashoreline in whichbreaking waves routinely form, between the furthest seaward limit at which incoming waves begin to break and the furthest landward extent reached by the uprush ofswash on thebeach.[21] The extent of the surf zone may change with thetide and local weather conditions.
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 drawmaps and establishboundaries for property ownership, construction projects, and other purposes required by civil law.
Any shallowchannel or trough with gently sloping sides, either natural or artificial. Man-made swales are often designed to managesurface runoff and increase rainwaterinfiltration.
1. The regular, undulating motion of the surface of a large body of water, e.g. of theocean; the succession of surface waves in theopen ocean which, though they may grow very large, do notbreak.[4]
Waste materials left over after the mining and processing of ore, during which a valuable mineral or metal is extracted from theuneconomic fraction accompanying it; the latter plus any substances applied in the extraction process are then discarded, often in spoil piles orponds near the mine, usually because it is prohibitively expensive or impossible to relocate, reuse, or otherwise destroy the discarded material. Mine tailings are distinct fromoverburden, which is displaced during mining but not processed, and are often nutrient-poor or toxic to living organisms, making it difficult for plant and animal life to reclaim the environs without further treatment.
Loose, broken rock fragments of any size and shape, usually coarse and angular, derived from and lying at the base of acliff or a very steep rock slope. Large quantities tend to accumulate on the slopes of highmountains by falling, rolling, or sliding from an eroding rockfall source.[11] Comparescree.
A small man-madepond orreservoir created by impounding a stream or by constructing a pit or basin to collect and hold rainwater or snowmelt.[4] Less commonly, the term may also refer to a natural pond or basin.
Traditionally, either of the two mid-latitude regions of the Earth defined by theirlatitudinal position between thetropics and thepolar zones, i.e. the region between latitudes23°30' N and66°30' N, or that between23°30' S and66°30' S.[4] In modern usage, the term may refer instead to regions of mild or temperate climate, regardless of latitude.
An increase in temperature with height above the Earth's surface, a reversal of the normal pattern, often observed in deepvalleys andbasins that are mostly or entirely enclosed by highmountain ranges.[5]
Amoraine that forms at the terminus orsnout of aglacier, marking its furthest advance. Debris transported byplucking and abrasion accumulates at the glacier's leading edge, where it is deposited in an unsorted pile of sediment as the ice begins to retreat.
One of a series of regularly spaced, horizontal, step-likeridges forming a distinctive ribbed pattern on a steep and usually grassy hillside, similar to an agriculturalterrace orlynchet but naturally occurring. Various explanations for their origins have been suggested, includingsoil creep,solifluction, and animal trampling.[4]
1. Consisting of, living on, or relating to land, as opposed to water or air; e.g. a terrestrial animal lives primarily on land surfaces rather than in the sea.[4]
2. On, of, or relating to the Earth, as opposed to other planets or to celestial phenomena occurring outside the Earth's atmosphere.[4]
1. A concept of theLaw of the Sea defined as the belt ofcoastal waters extending no more than 12 nautical miles (22 km) from a designatedbaseline (usually defined as themean low-water line) for a coastalstate and regarded as the sovereignterritory of the state; or more generally any area of water over which a state has legal jurisdiction, includinginternal waters, theexclusive economic zone, and potentially others.
A specific area or portion of the Earth's surface, especially one claimed or administered by a particular country; similar to though distinct from aregion.[5]
The line of lowestelevation within avalley orwatercourse, i.e. the line defining the longitudinal profile of an area with respect to the path followed by water draining from the area. Thalwegs may acquire special significance inpolitical geography because disputedborders along rivers are often defined by the river's thalweg. This has sometimes led to conflict because the thalweg may change naturally over time.
A shallow, roundedlake orpond occupying adepression resulting from the melting of ground ice orpermafrost, ubiquitous inthermokarst regions wherever there are flatlowlands with siltyalluvium and high ice content, including much of the North American and SiberianArctic. Many thaw lakes develop elongate shapes oriented with the long axis at a right angle to the prevailing wind.[15]
An optical instrument consisting of a small telescope, aspirit level, and graduated arcs mounted on a tripod, used insurveying and other applications to precisely measure angles between designated visible points in the horizontal and vertical planes.[4]
The tendency of bodies of water such aslakes to separate into distinct thermal layers along a vertical gradient, such that water temperature varies predictably with increasing depth. Stratification is typically a seasonal phenomenon, as exemplified by deep lakes attemperate latitudes during the summer, which often form a warm, turbulentupper layer near the surface; a colder, denserbottom layer; and atransition zone ofrapidly decreasing temperature in between. In all but the deepest lakes and oceans, these layers often disappear entirely in the spring and fall, whenconvective mixing makes the temperature more or less uniform at all depths, and may even invert if the surface freezes during the winter. Localtopography, wind patterns, and dissolved solutes also strongly influence the formation and disruption of stratified waters.[22]
A thin layer of water in an ocean or lake, typically between the non-circulatinghypolimnion and the warmerepilimnion, through which temperature changes more drastically with depth than it does in the layers above or below; e.g. temperature may decrease much more rapidly with increasing depth in this layer, commonly exceeding 1 °C (1.8 °F) per metre of descent.[4]
A type ofterrain characterized by expansive landscapes of smallhummocks interspersed with irregular,marshydepressions formed by the thawing of ice-richpermafrost. The unique landforms of thermokarst, includingpingoes,palsen,thaw lakes,alases, and linear and polygonaltroughs, result from variousperiglacial and thermo-erosional phenomena common in the Arctic and on a smaller scale in mountainous areas such as the Himalayas and the Alps.[15]
The vertical displacement of strata or rocks across the line of afault, varying from a few millimetres to hundreds of metres in height. Those rocks on the higher side of the fault are termedupthrow, while those on the lower side are termeddownthrow.[4]
A narrowinlet orestuary that is affected by the ebb and flow oftides from an adjacent ocean. Water in the lower portions of these channels tends to vary greatly in depth, salinity, electrical conductivity, and otherhydrological properties over the course of thetidal cycle, but is often slow-moving and rich in organic sediment drained from upstreamfreshwater portions, making them important habitats for many species.
An extensive, nearly horizontal, barren or sparsely vegetated tract of land at the edge of a sea or ocean that is alternately covered and uncovered by thetide.[11]
The total volume of water that flows in and out of a coastalinlet orestuary with each cycle of thetides, excluding any freshwater discharges; i.e. the difference in the inlet's volume between themean high andlow tides.[15]
The difference in height betweenhigh tide andlow tide at a given location. This range may vary over the course of the year, e.g. duringneap tides andspring tides.
The periodic rise and fall ofsea levels caused by the combined effects of the gravitational forces exerted by theMoon and theSun and theEarth's rotation.
A measure of how far apart places are in terms of the amount of time it takes to travel between them (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?).[5]
An interdisciplinary perspective,ontological framework, andvisual 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.
A region of the globe that observes a uniformstandard time for legal, commercial, and social purposes. Most time zones span about 15 degrees of longitude, and in each of these divisions themean solar time at an arbitrarily selectedmeridian (usually one near the longitudinal center of the division) is made the standard time across the entire zone. Time zones tend to follow political boundaries between countries and their subdivisions, however, rather than strictly following the same meridian, because it is convenient for areas in frequent communication to keep the same time.
A mathematical contrivance used to illustrate the linear, angular, and areal distortions that result whenprojecting information from a curved three-dimensional geometric model such as aglobe onto a two-dimensionalmap. A single indicatrix is traditionally a circle of determinate size drawn upon the surface of the globe, with center at specific coordinates; the extent to which this circle is deformed when the globe's coordinates are transformed onto a flat two-dimensional map makes apparent the nature of the distortion affecting nearby map features, such as the size and shape of landmasses, which might otherwise be difficult to visualize. Because distortion can vary greatly across a map, it is common for multiple indicatrices to be depicted at multiple points on the map, e.g. at major intersections ofmeridians andparallels.
TheBehrmann projection overlaid withTissot's indicatrices of distortion. The red circles are all the same size and shape; when projected onto the map with the rest of the coordinates, the deformation of a particular circle into an ellipse shows the direction and magnitude to which scale is distorted at that particular point on the map.
Summit B'stopographic isolation is the horizontal distance between the summit and the nearest point of equal elevation (about halfway up Summit A). Summit B'stopographic prominence is the vertical height between the summit and the lowest contour line that completely encircles it but no higher summit (at thecol between Summit B and Summit C).
A measure of the independence of amountain orhill defined as the vertical distance between itssummit and the lowestcontour line completely encircling it but containing no higher summit within it; or, equivalently, the difference between theelevation of the summit and the elevation of thekey col. Mountains with high prominence tend to be the highest points in their vicinity.
A type of diagrammaticmap which depicts the actual positional relationships between certain features but on which truescale is distorted and unnecessary detail is absent to accommodate other considerations (e.g. simplicity so as to aid understanding of a complex communications network or public transit system).[4]
Schematic route maps for public transit systems are examples oftopological maps: thistube map of theLondon Underground and several other passenger railways shows connectivity – i.e. the way in which the various lines connect particular stops and stations, which is the information most relevant to people riding the lines – but is not concerned with correctly depicting the orientation of the stations and is not drawn to scale.
In geographical studies, a discipline concerned with the mathematical analysis of enclosure, order, connectivity,contiguity, and relative position rather than with actual distance and orientation. Topological relationships are commonly expressed in terms of networks and depicted withtopological maps.[4]
A prominent, free-standing rockoutcrop that rises abruptly from the smooth slopes of a gently roundedhill orridge. In the United Kingdom, the term is also used to refer to the hill itself.
A medium-sized humansettlement that is generally larger than avillage but smaller than acity, though the criteria for distinguishing a town vary considerably in different parts of the world.
The rectangular system of land subdivision used to plat real property for sale and settlement in much of the agriculturally settled United States west of the Appalachian Mountains, established by theLand Ordinance of 1785.[5]
A road or path alongside a navigableriver,canal, or other inland waterway designed to allow land vehicles, draught animals, or a team of human pullers to tow a boat or barge.
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.[5]
Incartography, a misrepresented or nonexistent road or street that is deliberately included on amap (often outside the map's nominal area of coverage) for the purpose of detecting plagiarism by acting as acopyright trap: plagiarists who have copied other cartographers' work would find it difficult to explain the inclusion of the trap street on their map as coincidental. For this reason trap streets are often inconspicuous and given unique names. Many other map features are also used as copyright traps, including natural features andentire towns, and the implementation may also involve mislabeling features such as topographic elevations as well as making subtle stylistic alterations such as exaggerated or nonexistent bends in roads or rivers, ideally in a way that does not interfere significantly with navigation.[23]
1. Insurveying, a line orroute and the sequence of points on it at which observations or measurements are made, or the process by which such a sequence is established. The term may also refer more generally to any route or path traveled for any purpose.[2]
2. A relatively horizontal route taken so as to bypass obstacles when the primary goal is to move vertically, as in rock climbing and mountaineering.
Thelatitudinal orelevational limit of normal tree growth. Beyond this limit (i.e. closer to thepoles or at higher elevations) climatic conditions are too severe for such growth and trees are stunted or entirely absent.[5] The termcold timberline may also be used to emphasize that the limiting factor is temperature, particularly when distinguishing it from thedry timberline of arid regions, where tree growth is instead limited by the availability of water.[4]
The process of determining the location of a given point or object, especially its distance from an observer, by measuring only the angles to it from two known points along a common baseline, which represent two vertices of an imaginary triangle. The unknown point can then be fixed as the third vertex of the triangle, using the one known side and two known angles. Triangulation differs fromtrilateration, which measures distances to the point directly instead of angles.
By measuring the anglesa andb and the length of sideAB, the distance to the ship,d, can betriangulated using trigonometry.
The process of determining thelocation of a given point or object by measuring only thedistances to it from a sufficient number of other points; in particular, a method ofsurveying in which the location of one point relative to two or more others is determined by measuring the distances between all points (either ordinaryEuclidean distances orgreat-circle distances). When more than three distances are involved, the process may be calledmultilateration. Measurement ofdirection andangle is not strictly necessary for trilateration, though this information is often used in tandem with trilateration data.[2]
Characteristic of, located in, or relating to thetropics, either the specific parallels of latitude or the zone lying between those two parallels.[4]
tropics
Also called thetropical zone ortorrid zone.
The region of the Earth's surface surrounding theEquator and bounded by theTropic of Cancer (23.4° N latitude) and theTropic 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, regardless of latitude.[5] See alsotemperate zone andpolar zone.
Any elongated, generally U-shapedvalley,ravine,basin, or trench, natural or artificial, dry or wet. Particularly common usages refer to a submarine trench ordeep in theocean floor, or to a geologicalsyncline.[4]
The direction along the Earth's surface towards theGeographic North Pole. Geodetic true north differs frommagnetic north andgrid north, and also very slightly from astronomical true north, which is based on the direction of the northcelestial pole.
true south
Alsogeodetic south.
The direction along the Earth's surface that is exactly opposite (i.e. bearing 180 degrees) oftrue north, towards theGeographic South Pole.
A deep, greatly elongated, U-shapedvalley carved from land beneath a mass ofglacial ice, often near the margin of a continentalice sheet. Tunnel valleys may be up to 100 kilometres (62 mi) long, 2.5 kilometres (1.6 mi) wide, and 400 metres (1,300 ft) deep, and often occur side-by-side in a series of multiple parallel valleys.
A subglacial landform consisting of a flat-topped, steep-sidedvolcanic mountain formed whenlava erupts beneath an overlyingglacier orice sheet and melts through the ice to the surface, where it pools and solidifies into a level bed of volcanic rock; the glacier continues to gradually erode the surrounding landscape and, upon retreating, leaves behind a characteristicmesa-like rock formation.
Amisfit stream that is seemingly too small to have eroded the valley or passage through which it flows, often an indication that there was once a larger stream in its place.[9] Contrastoverfit stream.
Economically, a situation in which an increase in the size of the labor force will result in an increase in per-worker productivity.[5]
uniform region
A territory with one or more features present throughout which are absent or unimportant elsewhere.[5]
uninverted relief
Topographic surfacerelief which closely reflects the shape and orientation of the underlying geological structure, i.e. where hills and ridges coincide withanticlines and valleys withsynclines.[4] Contrastinverted relief.
Any area of land that is higher inelevation relative to another area, especially one that is populated by lowhills or situated atop aplateau. The term is often used as a conditional descriptor to distinguish relatedhabitats orecosystems, especially freshwaterriparian areas, on the basis of elevation above sea level. Upland areas are usually characterized by relatively fast-flowing waterways and hilly or rocky terrain. Contrastlowland.
The unrestricted growth of housing, commercial development, and roads (typically of low densities) over large expanses of land, usually within or near an existingurban orsuburban area and with little concern for civic planning. It is often considered a type ofurbanization and almost always carries negative connotations.
The study of the development ofcities andurban areas, especially from historical, architectural, orcivic planning perspectives.
urbanization
The process by which a humanpopulation shifts fromrural tourban residency, the gradual increase in the proportion of people living in urban areas such astowns andcities, 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.
An opening at the Earth's surface through which volcanic materials (lava, tephra, and gases) erupt. Vents can be at avolcano's summit or on its slopes; they can be circular (craters) or linear (fissures).[12]
Ascale used in certainmaps, such asraised-relief maps, that deliberately distorts the apparentelevation of the map'stopography to emphasize vertical features, which might otherwise appear too small to identify relative to the corresponding horizontal scale.
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 thehorizon or obstructed byterrain and natural or artificial objects.
village
A small, clustered humansettlement or community, usually larger than ahamlet but smaller than atown and often inrural areas, though the criteria for distinguishing a village can vary considerably in different parts of the world.
A computer-generated three-dimensional software model or representation of Earth or another planet, providing the user with the ability to freely move around in the virtual environment by changing the viewing angle and position, and also to map many different types of data upon the modeled surface, such as land use statistics, meteorological records, and demographic quantities. An example isGoogle Earth.
volcanic avalanche
Alsodebris 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.[12]
The scientific study ofvolcanoes,lava,magma, and the body of related geophysical phenomena known asvolcanism. It is a branch ofgeology andEarth science which seeks to understand the formation, activity, and dormancy of volcanoes, their current and historic eruptions, and how to predict them.
1. A dry, ephemeralriverbed which contains water only when heavy rainfall occurs.
2. Another name for avalley, used primarily in Arabic-speaking parts of the world.
warping
1. The slow, gentle deformation of the Earth'scrust over a wide area, resulting in a raising or lowering of the surface.[4]
2. (sedimentation) Any process, natural or artificial, whereby the low-lying land of a tidalestuary is flooded, leading todeposition of silt, mud, or clay.[4]
A low-lying area of unused or undeveloped land adjacent to ariver orstream, often within a naturalfloodplain, which is deliberately flooded when the water is high in order to prevent developed residential or agricultural areas from flooding. Washlands are thus sacrificed as a form offlood control, and may simultaneously function aswetlands andwildlife refuges.
1. Wild, uncultivated, uninhabited land, especially that which is barren or desolate, supporting little or no plant and animal life, such as is found in somedeserts.[4]
2. Land that yields little or no return when used for agriculture.[4]
3. Any land,common or otherwise, that was previously cultivated or developed but is now abandoned, and for which further use has yet to be found.[4] See alsobrownfield land.
Inhydrology andoceanography, a conceptual column of water extending from the surface of anocean,lake, orriver to the sediment of thefloor orbed, used to aid interpretation of properties and processes that vary along a depth gradient.
A low point or opening in aridge ormountain range carved by the erosional activity of flowing water and through which water continues to flow in the present day. Contrastwind gap.
The collection and presentation of point data related to the distribution, status, and sustainability of water supplies, generally by overlaying these data on a map showing administrative boundaries and population data, which can help to visualize and predict coverage issues and inform water management practices.
The level below the land surface at which subsurface material such as permeable rock is fully saturated with water. Thedepth of the water table reflects the minimum level to whichwells must be drilled forgroundwater extraction;[5] aspring,marsh, orlake results wherever the theoretical water table lies above the level of the land surface. The level of the water table is the boundary between thevadose zone and thephreatic zone. In many places its depth fluctuates seasonally, which accounts for the intermittent flow ofbournes. In some circumstances, there may be no regular water table; in others, aperched water table may exist.[4]
A low-lying area ofgrassland beside a natural stream or river, subjected to periodic flooding through controlledirrigation to increase agricultural productivity, typically via a series of man-madecanals or drains connected to the stream or river.[4]
An abrupt and steep or perpendicular descent in awatercourse, e.g. in thebed of ariver, resulting in a significant volume of water tumbling vertically downward or even freely falling by the pull of gravity. Waterfalls occur where the water's normally more level flow is interrupted by a nearly horizontal layer of hard rock overlying more easily eroded soft rock, or by the sharp edge of aplateau, or by the steep rock faces of ahanging valley, coastalcliff, or any otherescarpment orknickpoint. They may be permanent or ephemeral; many alpine waterfalls form seasonally on mountainsides as snow and ice melts during the summer.
A hollow ordepression in the ground, natural or artificial, in which water can collect, either from precipitation or fed by aspring, especially insavannas ordeserts where water is otherwise scarce; or a pool in thebed of anintermittent stream. Waterholes may be permanent or ephemeral.[4]
A flaterosion surface along theshore of a lake,bay, orsea that is formed by the undercutting and eventual collapse of asea cliff as a result of repetitive wave action.
A reference point in physical space used for purposes ofnavigation, especially when plotted on amap or in aGIS application as part of a traveledroute.[19]
A man-made obstruction built across the width of ariver that alters its flow and usually results in a change in the height of the river level, commonly by permitting water to flow freely over a low barrier before cascading down to a lower level. Weirs may serve many purposes, including decreasing or increasing the force of the current, maintaining water depth, or diverting orimpounding flow, typically for navigation, irrigation, fishing, to generate a head for awater mill, or to control outflow from alake orreservoir. Comparedam andbarrage.
Aweir creating a smallcascade on a river in Finland
welfare geography
An approach inhuman geography which considers the areal differentiation and spatial organization of human activity from the perspective of the welfare (health, prosperity, well-being, etc.) of the people involved, covering everything, positive or negative, contributing to the quality of human life and examining how and where observed inequalities between different societies arise.[4]
A hole or shaft dug into the ground to access liquid resources, especially water, oil, or gas, from beneath the Earth's surface. Water wells typically tap into naturalgroundwateraquifers and remain filled with water up to the level of thewater table, which can vary seasonally. The water is drawn up by a pump, or by using containers such as buckets that are raised mechanically or by hand. Anartesian well taps a water source held under considerable pressure.[4]
Thehalf sphere of the Earth that is west of thePrime Meridian and east of theantimeridian, and opposite theEastern Hemisphere. The Western Hemisphere includes all of the Americas, the Atlantic Ocean, and a large portion of the Pacific Ocean.
Any area of land orecosystem, natural or artificial, which is flooded or saturated by water, either seasonally or intermittently for short periods or permanently for years or decades,[13] and characterized generally by oxygen-poorhydric soils, distinct flora, highbiodiversity, and interactions between terrestrial and aquatic processes. Wetlands may befreshwater,brackish, orsaltwater ecosystems, and are often classified based on their sources of water (as withtidal wetlands,estuaries,floodplains,fens, andbogs) and/or their dominant vegetation (as withmarshes andswamps).
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 maintainingbiodiversity and ecological stability. Wildernesses are oftenprotected areas.
A tabular mass of rock that has become perched atop a pinnacle created by erosion (oftenaeolian) of the softer, underlying rock.[15] See alsodemoiselle,hoodoo, andpinnacle.
zibar
A type of lowsand dune with limitedslip face development, often occurring in the corridors between higher dunes.[15]
zonation
Inbiogeography and ecology, the separation of the Earth's flora and fauna into distinct groups occupying characteristic habitats,biomes,ecozones, or other idealized geographic divisions, primarily defined by climate, for the purpose of identifying and categorizing patterns inbiodiversity. The boundaries of the resulting "zones" may be loosely defined or even somewhat arbitrary. The term has also been extended to include any ecological unit with spatial dimensions.[15]
The imaginary point on thecelestial 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). Contrastnadir.
^abcdWade, Tasha; Sommer, Shelly, eds. (2006).A to Z GIS: An Illustrated Dictionary of Geographic Information Systems (2nd ed.). Redlands, California: ESRI Press.ISBN978-1-58948-140-4.
^J.K. Warren. "Sulfate Dominated Sea-Marginal and Platform Evaporative Settings: Sabkhas and Salinas, Mudflats and Salterns".Developments in Sedimentology, 50 (1991), pp. 69–187.
^abcMayhew, Susan (2023).A Dictionary of Geography (6th ed.). Oxford: Oxford University Press.ISBN9780192896391.
^Bowditch, Nathaniel, LLD; et al. "Glossary of Marine Navigation".The American Practical Navigator(PDF) (2002 ed.). Washington: National Imagery and Mapping Agency. Archived fromthe original(PDF) on 2017-05-17. Retrieved2010-11-16.{{cite book}}: CS1 maint: multiple names: authors list (link)
^17USC105, U.S. Copyright Office (December 15, 2009),"§ 105. Subject matter of copyright",U.S. Copyright Office – Copyright Law: Chapter 1, Title 17 of the United States Code, Circular 92, Washington, DC: U.S. Copyright Office, retrievedOctober 2, 2010,United States Government works: Copyright protection under this title is not available for any work of the United States Government, but the United States Government is not precluded from receiving and holding copyrights transferred to it by assignment, bequest, or otherwise.{{citation}}: CS1 maint: numeric names: authors list (link)
_on_Flowerpot_Island_-_Georgian_Bay_-_Ontario%2c_Canada_-_2_Sept._2011.jpg)
