Glossary of geography terms (N–Z)

This glossary of geography terms is a list of definitions of terms and concepts used in geography and related fields, including Earth science, oceanography, cartography, and human 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:


 * Glossary of geography terms (A–M) lists terms beginning with the letters A through M.
 * This page, Glossary of geography terms (N–Z), lists terms beginning with the letters N through Z.

Related terms may be found in Glossary of geology, Glossary of agriculture, Glossary of environmental science, and Glossary of astronomy.

N
nadir:

narrows:

A land or water passage that is confined or restricted by its narrow breadth, often a or a.

nation: A stable community of people formed on the basis of a common geographic territory, language, economy, ethnicity, or psychological make-up as manifested in a common.

national mapping agency: A governmental agency which manages, produces, and publishes, geographic data, and sometimes information that is specific to an individual or political territory, such as the United Kingdom's Ordnance Survey.

national park: A type of created and managed as a public park by a governmental authority for conservation purposes. Though individual governments designate national parks differently, they usually share the common goal of preserving natural or semi-natural landscapes (often ) for posterity and as symbols of national pride.

natural landscape: The original that exists before it is acted upon by humans. Contrast.

nautical mile: A unit of distance traditionally defined as the length equal to one of arc ($1/undefined$ of one ) along a of the Earth. Because the Earth is not a perfect sphere, the length of one minute of arc at the differs from that measured at the ; thus the modern internationally agreed-upon standard defines the nautical mile as the average of these two extremes: 1852 m. It is widely used in air, marine, and space  as well as for defining the limits of.

navigable: (of a place) Capable of being ; 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 describe and coastal. (of a vessel) In a navigable condition; steerable; seaworthy or roadworthy.

navigation: The determination of position and direction, generally by comparing the navigator's position to known locations or patterns. The process of monitoring and controlling the movement of a vehicle or craft from one place to another.

neap tide: A of decreased occurring semi-monthly as a result of the Moon being in quadrature 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 called neap high water or high water neaps, and that of the corresponding low waters is called neap low water or low water neaps. Compare.

nearshore: The part of a between the and the line at which the waves break.

neatline: A line separating the main body of a from the map's margin. On a standard map, the neatlines are the  and  delimiting the quadrangle.

neck: A narrow stretch of land with water on each side, e.g. an or. A narrow stretch of woodland or of ice. A high level, especially the narrowest part.

nehrung: A long separating a or  from the sea, especially one along the south coast of the Baltic Sea.

neighborhood:

A geographically localized within a larger,, , or area, particularly one which supports considerable face-to-face interactions between residents.

ness: In Scotland and parts of England, a or, or another name for a ; or a of a mountain.

nodal region: A region characterized by a set of places connected to another place by lines of communication or movement.

North Geographic Pole:

The point in the where the Earth's axis of rotation meets its surface. It is the northernmost point on Earth, directly opposite the, and defines the direction of at a  of 90 degrees North; its  can be assigned any degree value. Unlike the South Pole, the North Pole is not located on a continental landmass but in the middle of the Arctic Ocean. See also.

North Geomagnetic Pole:

The point in the where the axis of a theoretical simplified dipole passing through the center of the Earth would intersect the Earth's surface. It is to the. Because of the fluid nature of the Earth's molten core, the true axis of the Earth's magnetic field is not a perfect dipole, and so the Geomagnetic Poles and the actual lie some distance apart.

North Magnetic Pole:

The point in the at which the Earth's magnetic field points vertically downward. It is close to but distinct from the and the, and its precise location varies considerably over time due to frequent magnetic changes in the Earth's core. Its counterpart in the Southern Hemisphere is the, though the two poles are not directly opposite each other.

Northern Hemisphere: The of the Earth that is north of the. It is opposite the.

northing:

nubbin: A small, gentle consisting of a bedrock core dotted with rounded residual boulders. Nubbins form in a similar way to and.

nunatak:

O
oasis: A combination of a human and an area of cultivated vegetation in an otherwise desolate or semi-desert environment, made fertile when sources of, such as underground, irrigate the surface naturally or via man-made wells.

oblate spheroid: The approximate geometric : 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.

obsequent: (of a stream, river, or any natural water flow) Flowing in the direction opposite to that of the dip of the underlying rock strata. Contrast ' and '.

ocean: The vast, contiguous body of covering more than 70% of the Earth's surface area and surrounding the 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. The International 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.

ocean current:

ocean floor: See.

ocean trench: A long, narrow, very deep in the at the junction of two, where one plate is  steeply beneath the other, often penetrating the.

oceanography:

The scientific study of the Earth's 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 with along ; the  and geology of the ;, waves, and geophysical fluid dynamics;  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,, , meteorology, and climatology, among others.

oeconym:

A 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.

oecumene: See.

offshore: Moving away from the and toward the. Located at a point or in an area that is relatively close to but still seaward of the shore (as with an offshore ). Contrast. Seaward of the and the.

ogive: One of a series of regularly spaced bands of alternating height and color visible on the surface of some, resulting from seasonal patterns of and. Because ice flows faster near the center of the glacier, where there is less friction with the surrounding, ogives are usually shaped into conspicuous arcs that point towards the of the glacier.

ojo: In the southwestern United States, a small,, or , especially a.

open ocean: The part of the that is beyond or outside of areas, i.e. distant from land and not enclosed or partially enclosed by it. In, the term is synonymous with and is often defined as all oceanic waters seaward of any ; politically and economically, "open ocean" usually refers to all areas of a sea or ocean that are not within  (hence, any area that is within ) or, much more restrictively, not within any sovereign state's. See also.

open range: A cattle- or sheep-ranching area characterized by a general absence of fences and in which livestock are by law allowed to roam freely.

opisometer:

An instrument used to measure the lengths of arbitrary curved lines, especially the distances of rivers and roads on a.

ordinal directions: See.

ordnance datum (OD): Any used by the British as the basis for reporting  on. In modern Great Britain, the standard ordnance datum is the ODN, defined as the calculated from hourly observations of the tidal gauge at Newlyn, Cornwall, between 1915 and 1921. All heights shown on British maps are measured from this.

orientation: The position of or the act of positioning a person or object with respect to the directional points of a, especially the placement of a or instrument in the field so that a north–south line on the map or instrument lies  to a north–south line on the ground. Determining one's orientation at a given time is the chief aim of, and is generally of critical importance in.

orienteering:

orographic rainfall: Precipitation that results when moist air is lifted over a topographic barrier, such as a.

orography: A branch of and concerned with the scientific study and description of the  of the Earth, particularly of  and, and more broadly of any elevated.

orthodrome: See.

orthodromic distance: See.

orthophotograph:

An aerial photograph or satellite image that has been geometrically corrected or orthorectified such that the is uniform across all parts of the image, allowing the image to align with a particular. In an uncorrected aerial photo, distances on the ground may be distorted by, 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.

outback: In Australia, the vast, remote, sparsely populated. See also.

outcrop:

Any visible exposure of or ancient superficial deposits on the surface of the Earth; or more generally, any bare, rocky surface that is topographically distinct from the surrounding. Outcrops occur frequently in places where the rate of erosion exceeds the rate of weathering, such as on steep hillsides and mountains, river banks, and coastlines.

outwash: Rocky and sandy surface material deposited by that flows from a.

outwash plain: A smooth, flat of sandy or gravelly sediment formed by  deposited in front of the  of a melting, with larger material deposited closer to the.

overbank: sediment, usually consisting of fine sand, silt, and clay, that has been on the of a river or stream by flood waters that have broken through or overtopped the river's. The when a river or stream overflows the banks of its normal channel and spreads on to a floodplain, depositing such sediment.

overburden: Uneconomic material covering a mineral seam or bed that must be removed before the mineral can be extracted in strip mining.

oxbow: A wide U-shaped in a or. The formed when a meander is cut off from the of the river, creating a separate body of water.

P
Pacific-type coastline: See.

padang: An uncultivated, treeless in Southeast Asia, sometimes -like, supporting a scrubby -type vegetation common on leached sandy soils.

palisade: A wall of wooden stakes used as a defensive barrier. A line of bold, especially one showing basaltic columns.

palsa:

An elliptical dome-like mound containing alternating layers of ice lenses and peat or mineral soil, commonly 3 – high and 2 – long, and occurring frequently in in the  and subarctic zones of discontinuous permafrost.

paludal: Of or pertaining to a or, or to sediments that accumulate in a marshy environment.

pampa:

In parts of South America, a vast, fertile, ; or the temperate region encompassing these plains.

pan: Any shallow, generally rounded 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 a, which may be temporarily or seasonally flooded.

panhandle: See.

panhole:

A rounded or circular eroded into flat or gently sloping cohesive rock, typically shallow and ranging in diameter from a few centimeters to several meters, that is capable of collecting and holding rainwater and snowmelt. The term is sometimes used interchangeably with, though the latter may also refer to distinct geological features.

pantanal: In southern Brazil, a region consisting of a usually dry that is seasonally flooded by a.

pantograph: An instrument that enables the mechanical copying of a 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.

parallel: (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. (geography) Another name for a.

parish: A type of subnational division of a or used for religious, administrative, or other purposes.

park:

pass: See.

passive glacier: A with low rates of both and  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. Contrast.

pasture: Any land used for grazing by livestock, often a natural supporting native grasses and forbs with little or no active management by humans, as opposed to a, where the vegetation is mown for hay or silage.

peak: A pointed or protruding top or other vertical projection on a landform, e.g. a, especially implying the highest point or elevational maximum, i.e. the. A mountain as a whole, in particular a high,, or one.

pediment: An eroded, often bare rock platform, cut into the local, usually slightly concave and triangular in shape and extending over a considerable area at the foot of an abrupt mountain or face, the lower edge sloping gently away. Pediments form basal slopes of transport for material derived from the steeper slope above, and are characteristic of arid and semi-arid lands.

pediplain:

pedology: The scientific study of the morphology, composition, and spatial distribution of soils, with an emphasis on classifying soils and understanding their formation and evolution.

pedosphere: The uppermost layer of the Earth's that is composed of soils and subject to processes such as soil formation and erosion, a consequence of dynamic interactions between the,, , and.

pelagic zone:

peneplain: A low-relief leveled by long-term erosion, often implying a landscape that is in the final stages of 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.

peninsula: A piece of land surrounded by water along the majority of its border while still being connected to a from which it projects.

perched water table:

perennial stream: A that normally flows continuously throughout the entire year, without drying up, as opposed to a transient or.

pericline:

periglacial: Of or relating to an area located adjacent to or on the margin of an or, either presently or in the past, or to associated glacial or cryological phenomena. Describing any place where seasonal cycles of freezing and thawing modify the landscape in a significant manner.

periplus:

A historical manuscript listing the, safe, and coastal that a maritime vessel could expect to encounter along a or , arranged in order according to a particular direction of travel and including the intervening distances between them. See also.

permafrost: A permanently frozen layer of soil, or any ground at high or high that remains frozen year-round.

petrographic province:

photic zone:

The uppermost layer of a (e.g. a or ), defined by the maximum depth to which sunlight can penetrate the. The photic zone usually supports large populations of photosynthetic organisms and the majority of the aquatic life inhabiting the body as a whole.

photogrammetry: 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. The science of extracting three-dimensional measurements from two-dimensional data, such as images.

phreatic water: See.

phreatic zone:

The part of an that is below the, where nearly all pores and fractures are fully saturated with water. Contrast.

physical geography:

The branch of geography that studies processes and patterns in the natural environment, such as the,, , and , as opposed to the cultural or. Along with, it is one of the two major sub-fields of geography.

physiographic region: A portion of the Earth's surface with a common and morphology.

physiography: Another name for.

piedmont:

Any geographic region lying or formed at the base of. The term is used primarily in the southeastern United States to refer to a broad region extending from the Blue Ridge Mountains to the Atlantic coastal plain.

piezometric surface:

pingo: A landform consisting of a relatively large conical mound of soil-covered ice, commonly 30 – high and up to 1000 m in diameter, and that grows and persists in part as a result of hydrostatic pressure within and below the of  and subarctic regions.

pinnacle:

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 also ', ', ', ', and.

pit crater:

A type of formed by the of the surface lying above a void or empty chamber. Pit craters are similar to and are often associated with volcanic activity, but lack the ejecta deposits and  flows of.

place: A particular point on the Earth's surface, or the area surrounding such a point, having or encompassing a definite ; a, often specifically named, that is identifiable in social interaction because humans have endowed it with meaning or purpose; a 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 of.

place identity:

place utility: The measure of approval or satisfaction accorded by an individual to a in his or her ; the value or usefulness of a particular place as perceived by a particular person. Dissatisfaction with place utility may result in.

placename: See.

placer: (mineral deposit) An accumulation of valuable minerals, particularly gold, formed by gravity separation from a source rock during natural sedimentary processes. The minerals, from rocks or veins, are washed out by streams and mixed with deposits of sand or gravel, from which they can then be extracted by placer mining. (reef) A flat, shallow or submerged beneath the ocean surface, often with a sandy bottom suitable as an  for seagoing vessels.

plain: Any broad, flat expanse of land that generally does not show significant variation in topography or.

plane table:

A small drawing board mounted on a tripod used in, 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-dimensional, 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 about and therefore do not show and represent only horizontal distances.

plat: A map, drawn to scale, showing the legal boundaries and divisions of a tract of land, particularly of the type used to divide real property for sale and settlement in the  of the United States.

plate tectonics: A geologic theory that the bending (folding) and breaking (faulting) of the solid surface of the Earth results from the slow movement of large sections of that surface called plates.

plateau:

A large area of relatively flat terrain that is significantly higher in elevation than the surrounding landscape, often with one or more sides with steep slopes.

platted land: Land that has been divided into lots.

playa: An exceptionally flat, arid that is the dry of an evaporated ; or the shallow, usually saline lake itself which periodically forms when the basin is temporarily covered with water, e.g. after substantial rainfall. See also.

plucking:

An erosional phenomenon whereby a gradually scours and displaces pieces of rock from the beneath it and transports them along with the glacial flow of ice and debris. As the glacier moves down a, 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, becoming. The term is also sometimes used to describe the similar process of, which occurs on a smaller scale in fast-moving and.

plug: A cylindrical mass of volcanic rock marking the neck of an ancient, especially one exposed by denudation of the surrounding.

plumb line: A vertical reference line created by suspending a weight, known as a plumb bob or plummet, 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 the, plumb lines are used to establish a vertical in a wide range of applications, particularly in to determine the  of a point in space, and often in combination with an instrument to set the instrument precisely over a fixed.

plunge pool: A deep at the base of a into which the water drops with great force,  and  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.

plural society: A situation in which two or more groups occupy the same territory but maintain their separate cultural identities.

point bar: A feature made of that accumulates on the inside bend of a   or, below the  and often directly opposite a. Point bars are usually crescent-shaped of sand, silt, or gravel, similar to  and.

polar aspect: A planar with its origin located at either the or the.

polar circle: Either of the two circles of enclosing the Earth's : the in the Northern Hemisphere and the  in the Southern Hemisphere.

polar ice cap:

Either of the two very large regions near the Earth's geographical poles that are seasonally or persistently covered in ice, which occurs because high-latitude regions receive less direct solar radiation than other regions and therefore experience much lower surface temperatures. The Earth's polar ice may cover both land and sea, and varies in size seasonally and with long-term climate change. They typically cover a much larger area than true and are more correctly termed.

polar region: Either of the two high-latitude regions surrounding the Earth's geographical poles (the and ), which are characterized by frigid climates and extensive. The polar region of the Northern Hemisphere is often simply called the and that of the Southern Hemisphere is called the.

polder:

A low-lying tract of land enclosed by, forming an artificial hydrological entity by creating land from a naturally inundated area, e.g. by from a lake or sea, or by building barriers around a or  and then draining it. All polders are eventually below the surrounding some or all of the time, making them especially prone to flooding, and they often require continuous draining.

pole: An extreme geographical point, especially one of a pair. Either of the two points where the Earth's axis of rotation meets its surface, i.e. the geographic poles, representing the northern and southern extremities of terrestrial : the and the. Either of the two ends of the generated by the dynamo in the. These ends may refer either to the true magnetic poles, known as the and the, which are not directly opposite each other, or to the  poles of a hypothetical perfect dipole passing through the Earth's center, known as the  and the.

pole of inaccessibility: 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.

political geography: The study of both the spatially uneven outcomes of political processes and the ways in which political processes are themselves affected by spatial structures. A sub-discipline of, its primary concerns can be summarized as the relationships between people, state, and territory.

polje:

A very large found in regions, enclosed within a, usually elliptical, with a flat  either of bare limestone or covered by, and generally surrounded by steep limestone walls; or more broadly any enclosed or nearly enclosed. The term is used primarily in the Slavic-speaking world.

polynodal: Many-centered; having many nodes.

polynya: An area of unfrozen seawater surrounded by an otherwise contiguous area of or. Polynyas are often formed along polar coastlines through the action of katabatic winds, but may also form in the.

pond: A natural or artificial of standing water that is usually smaller than a.

populated place: A place or area with clustered or scattered buildings and a permanent human population (a,, , or ) that is referenced with.

population: A collection of organisms of the same group or species which live in a particular geographical area. In the context of geography, it often refers to a collection of humans and is represented at the most basic level as the number of people in a given geographically or politically defined space, such as a,, , , or the entire world.

population geography: A branch of that studies the ways in which spatial variations in the composition, distribution, migration, and growth of are related to the nature of places. This often involves factors such as where populations are found and how the size and composition of these populations is regulated by the processes of fertility, mortality, and migration.

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.

positioning system: Any technology or mechanism used to determine the position 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/or technologies capable of providing coverage ranging from or regional to  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.

potamology: The branch of that studies, including the processes and phenomena that occur at their, , and ; the structure and morphology of ; and the water, thermal, ice, and sediment regimes that affect and are affected by river.

potentiometric surface: See.

pothole:

Any smooth, bowl-shaped or cylindrical hollow, generally deeper than it is wide, that is carved into the rocky of a such as a  or. Fluvial potholes are created by the grinding action of stones or coarse sediment kept in perpetual motion in the same spot by the turbulence of the current. The term is also used to refer to beneath, which are created by similar processes. See also. A vertical or steeply inclined shaft in a limestone deposit. In the Great Plains of North America, a shallow, generally less than 10 acre in area, occurring between or on relief on a  and often filled by an intermittent  or. Another name for a. Another name for a.

prairie: A type of temperate grassland ecosystem dominated by a characteristic composition of grasses, herbs, and shrubs, rather than by trees. The term is used primarily in North America, but similar ecosystems can be found across the world.

Precambrian rock: The oldest rocks, generally more than 600 million years old.

presque-isle: A connected to the by an extremely narrow  of land such that the land at its distal end is very close to being an. See also.

prevailing winds: The direction from which winds most frequently blow at a specific geographic location.

primary sector: That portion of a region's economy devoted to the extraction of basic materials (e.g., mining, lumbering, agriculture).

Prime Meridian: The imaginary line running from north to south through the Royal Observatory in Greenwich, England which is assigned a of 0 degrees and is therefore used as the reference point for all other lines of longitude.

proglacial: Preceding, in advance of, or in front of the or of a, either spatially or temporally.

progradation: The natural extension of a into a body of water by the gradual accumulation of sediment over time, especially as a result of  processes, such as the protrusion of a  into the sea. This occurs when the volume of sediment carried by the river and deposited at its mouth exceeds the volume lost through, sea level rise, or coastal erosion.

prominence: A conspicuous high point that projects above or beyond its surroundings, e.g. a or a. See.

promontory: A raised mass of land that projects into a or a. Compare ' and '.

protected area: Any clearly defined geographic space in which human occupation or the exploitation of resources is limited or forbidden through legal or other effective means because of the area's recognized natural, ecological, cultural, or historical value.

province: A type of second-level administrative division within a or.

psychogeography:

public land: Any land area held and managed in the public domain by a federal or local government.

pueblo: A type of Indian village constructed by some tribes in the southwestern United States. A large community dwelling, divided into many rooms, up to five stories high, and usually made of adobe. This is also a Spanish word for town or village.

puna: An in the central Andes Mountains of South America, or any of the various high-altitude ecosystems encompassing it, including cold and alpine.

Q
quadrangle:

A standard division of the Earth's surface area used in produced by the United States Geological Survey. Quadrangles are four-sided polygons of varying size, depending on the map series; for example, 7.5-minute quadrangles divide the mapped surface into quadrilaterals measuring 7.5 minutes (0.125 ) of by 7.5 minutes of, with each 7.5-minute map showing the  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.

quagmire: See.

quarry: A place from which stone, rock, sand, gravel, slate, or aggregate is excavated from the ground, especially a large man-made pit that is exposed to the open air.

R
raft ice: A jumbled mass of blocks of ice that impedes the flow of water in a river or stream.

rail gauge: The distance between the two rails of a railroad.

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).

rain shadow: An area on the (downwind) side of a mountain or mountain range that receives greatly diminished precipitation.

rainforest: Any characterized by abundant rainfall, dense layers of vegetation, and extremely high. Rainforests are found in both tropical and temperate regions. The term is sometimes used to refer to a tropical rainforest.

rake: A sloping on a mountainside or rock face. The term is used primarily in Scotland.

rapid:

A section of a or where the  is sufficiently steep, the rate of flow is sufficiently fast, and/or the  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, often forming large white-capped,, , 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 their, where channels are relatively shallow and narrow and often pass through mountainous or highly eroded terrain, than to downstream portions near their , where channels tend to be deeper and wider.

raster: 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 with and is associated with values containing a discrete amount of information from one or more layers or "". Raster models are useful for storing and presenting large amounts of complex multivariate data that vary continuously across space, as is commonly encountered in, aerial photographs, satellite imagery, and many other aspects of. Raster data are contrasted with, which instead store and represent geographic information in the form of points, lines, and polygons.

ravine: A slope landform of relatively steep sides, sometimes with an intermittent flowing along the downslope channel. Ravines are typically narrower and shallower than, larger than, and smaller than.

reach: A relatively straight, level, uninterrupted segment of a,, , or other , or of an of a sea or ocean, traditionally defined by its ability to be sailed in one "reach" (i.e. on a single point of sail, without tacking) and also usually implying a line-of-sight stretch of water between two bends or horizons, or between , , stream gauges, or any other. 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. In, 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.

reclaimed land: 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 of efforts such as those designed to bury following the cessation of mining operations. An area of land, commonly submerged underwater in its natural state, that has been protected by artificial structures such as and drained for agricultural or other purposes (e.g. a ).

reef: A submerged -like or -like structure built by sedentary calcareous organisms, especially corals, in shallow marine waters, and consisting primarily of their skeletal remains, though often still supporting living colonies as well. Reefs may also be partially composed of rocks, sand, gravel, or seashells. They are locally prominent above surrounding sediments deposited on the, rising to or nearly to the water's surface.

re-entrant: See.

reference ellipsoid: A mathematically defined surface that approximates the for use in or  definitions. Because of their relative simplicity, reference ellipsoids are used in geographic applications as preferred surfaces on which computations are performed and point coordinates such as,, and  are defined.

reg: See.

region: An area having some characteristic or characteristics that distinguish it from other areas; a that is of interest to people, for which one or more distinctive traits (e.g. climate, economy, history, etc.) define its identity.

regionalism: The feeling or expression of a common sense of identity, purpose, or group consciousness associated with a particular geographical, e.g. the Southern United States, Scandinavia, or Lower Egypt, often combined with the creation of institutions that accommodate that particular identity and shape public action. A movement to decentralize central government, placing administrative responsibility instead at a level intermediate between that of the and that of smaller local or units. 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. In linguistics, a word or phrase originating in, characteristic of, or limited in usage to a particular region.

regiopolis: A located outside the core of a that serves as an independent driving force for political, economic, or cultural development within a larger. Contrast.

regolith: A layer of loose, unconsolidated, heterogeneous superficial deposits (e.g. soil, sediments, broken rock, volcanic ash, wind-blown material, etc.) overlying solid.

relative height: See.

relative relief: The or of one location relative to another location; the difference between the highest and lowest points within a given geographical area.

relief: See.

relief map: See.

remote: (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.

remote sensing: The gathering of information about an object or place from a remote location (i.e. without making physical on-site observations), most commonly by the use of satellite- or aircraft-based electromagnetic sensor technologies.

representative fraction (RF): The fraction expressing the ratio between the distance measured between two points on a and the corresponding actual distance measured between those points in the real world, used to indicate the map's. 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 of $1/1,000,000$, often written as 1:1,000,000 or 1:1 mn, means that one inch (or one centimetre) on the map itself is equivalent to one million inches (or centimetres) in the real world. One statute mile is equal to 63,360 inches, so 1,000,000 inches is approximately 16 miles.

reservoir:

An artificial or an artificially enlarged natural lake that is used to store water. Reservoirs are often created by the construction of a or  in a natural.

resource: Anything that is both naturally occurring and of use to humans.

retroreflector:

rhumb line:

A line drawn on the surface of a sphere (or on an idealized representation of the Earth) which crosses all of at the same angle, and which therefore has constant  relative to  or.

ria: The seaward end of a valley which has been flooded as a result of a rise in sea level.

ribbon development: The of residential and economic communities along the main routes of communication and transportation radiating from a or other developed area, because of the advantages of accessibility, relatively inexpensive land, and trade from passers-by.

ribbon lake: A long, narrow, finger-shaped, especially one found in a and dammed by a rock bar or.

ridge: An elongated raised landform which forms a continuous elevated crest for some distance, such as a chain of or. The line formed by the highest points, with only lower terrain immediately to either side, is called the ridgeline.

ridge and swale:

riegel: An of resistant that forms a bar across a  and often acts as a  to impound the waters of a.

rift valley: A that has formed along a long, narrow continental trough bounded by normal ; a of regional size.

rill: A shallow water channel, generally not more than 6 in 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 called.

rimaye: See.

riparian rights: See.

riparian zone:

The area along the margins or of a,, , , or other ; 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 important with characteristics of both terrestrial and aquatic ecosystems, and often support dense hydrophilic plant communities of high. They often overlap with and by some definitions may be considered.

river: A natural, usually, that flows towards an , , , , or in some cases into an or an underground. See also.

river pocket: An area of land enclosed within the bend of a, especially where the bend is extended or pronounced (e.g. a ) and the only road access is along the. The term is used primarily in Australia.

riverine:

Located on or inhabiting the or the area adjacent to a or.

rivulet: A very small or, often or ; a.

road map:

Any 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 including as well as  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.

roadstead: A, natural or man-made, that is sheltered from, , and , and is therefore a known general station in which ships can without dragging or snatching.

rôche moutonnée: See.

rock mill: See.

route: 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. A circuit traveled in delivering, selling, or collecting goods, e.g. by a mail carrier.

routefinding: The determination of a viable 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 aid, instead relying entirely on recognition of natural features and and quick estimations of distance, scale, ease, and safety.

rural: An adjective describing any geographic area located outside areas of significant human population such as and ; all population, housing, and territory not included within an area is often said to be rural. Rural areas are typified by low, very small, and expansive areas of agricultural land or.

S
sabkha:

saddle: For a given pair of summits, the region surrounding the low point or  on the  connecting the two summits; mathematically, it is the critical 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 to between the two summits.

salient:

Any narrow, elongated protrusion of a larger, either physical or political, such as a state.

salt marsh:

A natural ecosystem in the upper, between land and open  or, that is regularly flooded by the  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 nearby from coastal erosion.

salt pan:

A large, flat expanse of land naturally covered with salt and/or other minerals, usually to the exclusion of virtually all vegetation. Salt pans are common in, where they form by the precipitation of dissolved mineral solids as a large body of water evaporates. See also.

saltwater:

Any naturally occurring water, especially the water from a or, characterized by high concentrations (between 3 and 5% by volume) of dissolved salts, primarily sodium and chloride ions, relative to or. 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.

sand dune: See.

sand sea: See.

sandbar: See.

sandplain: A flat area where the soil or ground surface is covered with or composed of sand that has been transported from elsewhere and by wind or oceans, rather than by weathering of the local.

sandur: See.

satellite navigation:

A method of or an autonomous geospatial that relies on artificial satellites in orbit around the Earth to transmit time signals at radio frequencies along a  to electronic receivers on the surface, which can then use this information to determine their 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.

satellite state: A formally independent or polity which nevertheless depends economically, politically, or militarily upon, or is strongly influenced or controlled by, another, more powerful state.

savanna:

A mixed - 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.

scale: The relationship between a linear measurement on a and the distance it represents on the Earth's surface. The level at which a geographical phenomenon occurs or is described.

scarp:

A steep face or slope terminating an elevated surface of low, formed either because of faulting or by the erosion of inclined rock strata.

schrund: See.

scroll: A narrow stretch of added to the outer end and downstream side of between enclosed  on a river. A type of consisting of a low, narrow running in line with the curve of a meander, formed when the river overflows its.

sea: Any large body of surrounded in whole or in part by land. Any large subdivision of the World Ocean. "The sea" is the colloquial term for the entire interconnected system of salty bodies of water, including, that covers the Earth.

sea lane:

A navigable route across a wide waterway such as an,, or large that is regularly used for maritime trade by large vessels or ships because it is safe, direct, and economical.

sea level: The average level of the surface of one or more of Earth's from which heights such as and  are commonly measured. Often called mean sea level (MSL), it is a type of standardized  that is used in numerous applications, including,, and. Mean sea level is commonly defined as the midpoint between the mean low and mean high at a particular location.

sea stack: See.

seabed:

The bottom of a or. As with land, the ocean floor may have, , , and.

seaboard: Any extensive region of land adjacent to the, broadly synonymous with or coastline.

seamount: A (often a ) rising from the whose  does not reach the water's surface and which is therefore entirely submerged and not an  or.

search space: In, 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 current.

seaway: See.

second home: A seasonally occupied dwelling that is not the primary residence of the owner. Such residences are usually found in areas with substantial opportunities for recreation or tourist activity.

secondary-intercardinal directions: The set of eight intermediate directions used in and, each of which is located halfway between a pair of : north-northeast (NNE), east-northeast (ENE), east-southeast (ESE), south-southeast (SSE), south-southwest (SSW), west-southwest (WSW), west-northwest (WNW), and north-northwest (NNW). They may or may not be explicitly labeled on a.

secondary sector: That portion of a region's economy devoted to the processing of basic materials extracted by the.

sector principle: The principle on which political claims to territory in the have historically been made, such that the territories are divided into arbitrary wedge-shaped sectors, each one having an apex at the geographic pole and including outer areas of both land and sea extending to a particular. Because of the limited accessibility and generally low material value of both the and, the sector principle has emerged as a means of formally sharing responsibility for these regions between the world's sovereign states.

sector theory:

sedimentary rock: Rock formed by the hardening of material deposited in some process; most commonly sandstone, shale, and limestone.

seismograph: A scientific instrument that detects and records vibrations (seismic waves) produced by.

selva: A dense forest, especially in the Amazon basin of South America.

sense of place:

serac:

A large block or pillar of ice formed by the intersection of numerous where the glacier fragments as it reaches a steep slope. Seracs are usually found in, often in large numbers, in mountainous terrain.

settlement:

Any place where people live and form communities.

shadow effect: The phenomenon by which a large, well-served 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.

shakehole: See.

shallows: An area of water of relatively little depth, e.g. in a sea, lake, or river.

sheepback:

A rock formation created by the passage of a over underlying, which often results in asymmetrical erosional forms created by abrasion on the upstream side of the rock and plucking on the downstream side.

shelf sea: A relatively shallow, generally less than 300 m deep, beneath which a portion of a is submerged.

shield: A broad area of very old rocks above sea level that is usually characterized by thin, poor soils and low population densities.

shield volcano: A class of that resembles an inverted warrior's shield, with long gentle slopes produced by multiple eruptions of fluid flows.

shoal:

A natural submerged,, or that consists of or is covered by sand or other unconsolidated material and rises from the of a  to just below or above the surface.

shore:

The fringe of land at the edge of a large, such as an, , or. Compare.

shore platform: See.

shoulder:

shoulder drop: See.

side valley:

sinkhole: A formed when the roof of a collapses, usually found in areas of limestone rock.

site: The features of a related to the immediate environment in which the place is located (e.g., soil, subsurface, geology,, etc.).

situation: The features of a place related to its location relative to other places (e.g., accessibility, hinterland quality).

skerry: A small, rocky or, often one of a series lying just offshore and parallel to the main trend of the, over which large waves may break at high tide or in stormy weather.

sky island:

slack: A shallow hole or hollow among or mud banks.

slack water:

The brief period of time during which a susceptible to is completely unstressed because the tidal stream is almost still, i.e. there is no movement in either direction in the tidal current, usually the period immediately before and after the  and  marks, prior to the tide reversing direction.

slant range: The distance along the relative direction between two points, especially two points which are not at the same relative to a specific. If the two points are at the same elevation, the slant range equals the horizontal distance.

slash: In the southeastern United States, a low-lying or area, overgrown with shrubs and cane grasses and favorable for the growth of the slash pine and related trees. The debris of felled trees, especially in a that has been subjected to slash-and-burn agriculture.

slide: 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 a landslide or avalanche. The mass of material moved or deposited by such an event, and which has become fixed or settled upon the landscape.

slip-off slope: The more gently sloping of the two of a or, usually on the inside bend of a, as opposed to a.

slope: 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). See also.

slough: A type of – usually a, a shallow, or a branching from or feeding into a  – in which water tends to be stagnant or flows only very slowly on a seasonal basis.

slum: A residential settlement or, usually in or near an 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.

smog: A mixture of particulate matter and chemical pollutants in the lower atmosphere, usually over urban areas.

snout:

The lowermost margin or extremity of a, always either gradually advancing or retreating, sometimes partially hidden by material, and commonly featuring a from which meltwater flows.

snowline: 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 high. This elevation varies widely with, local climate, directional, and steepness of , such that the snowline may be very different on different mountains in the same , on different faces of the same mountain, or on the same face in different years.

social trail: See.

soil horizon: A distinct layer of soil which can be distinguished from other layers in vertical cross-section.

solution pan: See.

solubility: The degree to which a substance can be dissolved in another substance; in a geographical context, the characteristic of soil minerals that leads them to be carried away in solution by water. See also.

sound: A large of a sea or ocean that is larger than a, deeper than a, and wider than a. A narrow sea or ocean between two landmasses.

South Geographic Pole:

The point in the where the Earth's axis of rotation meets its surface. It is the southernmost point on Earth, directly opposite the, and is located on continental land in Antarctica at a of 90 degrees South; its  can be assigned any degree value. See also.

South Geomagnetic Pole:

The point in the where the axis of a theoretical simplified dipole passing through the center of the Earth would intersect the Earth's surface. It is to the. Because of the fluid nature of the Earth's molten core, the true axis of the Earth's magnetic field is not a perfect dipole, and so the Geomagnetic Poles and the actual lie some distance apart.

South Magnetic Pole:

The point in the at which the Earth's magnetic field points vertically downward. It is close to but distinct from the and the, and its precise location varies considerably over time due to frequent magnetic changes in the Earth's core. Its counterpart in the Northern Hemisphere is the, though the two poles are not directly opposite each other.

Southern Hemisphere: The of the Earth that is south of the. It is opposite the.

space economy: The locational pattern of economic activities and their interconnecting linkages.

spatial analysis: Any of the wide variety of formal techniques used to study entities according to their topological, geometric, or geographic properties. 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.

spatial citizenship: The participation of individuals and groups of laypeople in decision-making about and social rules in public spaces through the reflexive production and use of geographic media such as,, and 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.

spatial interaction: Movement or exchange between locationally separate places.

spatial reference system (SRS):

A local, regional, or global system used to locate geographical entities and which defines a specific as well as transformations between different systems.

spatiomap:

spirit level:

spit:

A type of or extending from a  into an  or  and which develops by the  of sediment as a result of. Spits form where the direction of the sharply changes direction, such as at a, and often develop a "hooked" or recurve shape at their distal ends.

spot elevation:

A point on a or whose height or  above a specified  (often ) is explicitly annotated, usually by a numerical elevation value printed immediately adjacent to a dot or  indicating the point itself. often include spot elevations, wherever practicable, for the of,, , and ; ;  and  of roads, trails, and waterways; water surfaces of  and ; notable low points such as the local elevational minimum of a ; very large flat areas; and any other point which may be  to the map user.

spreading ridge: See.

spring: Any location where naturally emerges from an underground to the Earth's surface.

spur: A lateral or other salient landform protruding from the side of a,, or the main crest of a and typically surrounded on at least three sides by steep hillsides.

stack:

A landform consisting of a steep and often vertical column or columns of rock above the surface of the sea and formed by erosion due to wave action. See also.

stage:

In, the height of the surface of a or at a particular location and a particular point in time, with respect to a reference height such as its  or a position on its, and used especially to monitor seasonal changes in discharge and flooding.

stand: An area of vegetation dominated by a single species, e.g. a stand of oak trees.

Standard Metropolitan Statistical Area (SMSA): A statistical unit of one or more counties that focus on one or more central cities larger than a specified size, or with a total population larger than a specified size. This is a reflection of urbanization.

state: A compulsory political organization with a centralized government that maintains a monopoly of the legitimate use of force within a certain geographical territory. See.

steilhang: A steep,, or , especially one with an average between 30 and 60 degrees from the horizontal. The term is used primarily in the German-speaking world.

steppe: An characterized by expansive grassland without trees apart from those near rivers and lakes.

stopbank: See.

stoss: An adjective describing the side of a or that faces the direction from which an advancing  or  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 the.

strait: See.

strandline: A or, 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. See also.

strath: A large river, typically wider and shallower than a. The term is used primarily in Scotland, Australia, and Canada.

stratovolcano:

A steep-sided built by flows and  deposits.

stream: A natural body of water in which flows between the of a. Long, large streams are called.

stream order:

The hierarchical classification of all of the branching comprising a river system or, usually by assigning an ordinal number to each individual indicating the magnitude of its  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 the ) 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 or, terminating at the , is reached.

streambed:

The bottom of the of a or, usually covered with rocks, sand, or debris and totally devoid of terrestrial vegetation if the stream has flowed recently. The bed is generally considered the part of the channel up to the normal water line, whereas the is the part above the water line.

strip map: A covering only a narrow band of territory in which the user is interested, e.g. alongside each side of a trail or vehicle route.

subcontinent: A large forming a contiguous part of an even larger, though often separable by physiographic or political boundaries, e.g. the Indian subcontinent; or a non-contiguous but still very large landmass that is smaller than one usually termed a continent, e.g. Greenland.

subduction zone: The place where two lithospheric plates come together, one riding over the other. Most volcanoes on land occur parallel to and inland from the boundary between the two plates.

subglacial: Of, relating to, or formed on or by the underside of a. Contrast ' and '.

sublittoral: Of or relating to the area of the sea between the and the edge of the. Compare. Of or relating to the deepest parts of a or other large body of freshwater, distant from the, where plants cannot root. See also.

subsequent: (of a stream, river, or any natural water flow) Flowing along a determined by the structure of the local. Contrast ' and '.

suburban: An adjective describing a mixed-use or residential area existing either as an ancillary part of an area or as a separate community within commuting distance of a ; a place of this type is called a suburb. Suburbs are often defined by commuter infrastructures and have lower population densities than inner-city.

suburbanization: The process by which a human shifts from to  residency, or the gradual increase in the proportion of people choosing to live in suburban neighborhoods which act as satellite communities within commuting distance of larger, centralized urban areas. Suburbanization is inversely related to.

summit:

A point on a surface that is higher in than all points immediately adjacent to it. Mathematically, it is a local maximum in elevation. The highest point of a or  is often referred to as the summit.

superglacial:

Of or relating to the surface or to the environment at the surface of a. Contrast ' and '.

surf zone:

The area along a in which routinely form, between the furthest seaward limit at which incoming waves begin to break and the furthest landward extent reached by the uprush of  on the. The extent of the surf zone may change with the and local weather conditions.

surface water: Water present on the surface of the Earth, such as in a,, , or , as opposed to.

survey marker:

surveying: The science, technique, and profession of determining the terrestrial or three-dimensional positions of points on the surface of the Earth and the distances and angles between them. These points are often used to draw and establish for property ownership, construction projects, and other purposes required by civil law.

swale: Any shallow or trough with gently sloping sides, either natural or artificial. Man-made swales are often designed to manage and increase rainwater infiltration.

swallet: See.

swamp: A forested, often occurring along a large or on the shores of a large.

swell: The regular, undulating motion of the surface of a large body of water, e.g. of the ; the succession of surface waves in the which, though they may grow very large, do not. A rise or uplift on the deep. Any dome-shaped, often a or other geological uplift, covering a very large area.

swirlhole: See.

syncline:

synekism:

syrt: A or elevated flatland in Russia and Central Asia; a kind of.

T
table:

A,, or with a relatively flat, often expansive area. See also.

tablemount: See.

taiga: A moist subarctic coniferous that begins where the ends and is dominated by spruces and firs.

tailings:

Waste materials left over after the mining and processing of ore, during which a valuable mineral or metal is extracted from the uneconomic fraction accompanying it; the latter plus any substances applied in the extraction process are then discarded, often in spoil piles or near the mine, usually because it is prohibitively expensive or impossible to relocate, reuse, or otherwise destroy the discarded material. Mine tailings are distinct from, 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.

talik: A layer of year-round unfrozen ground between or within layers of, or between the and permafrost.

talus: Loose, broken rock fragments of any size and shape, usually coarse and angular, derived from and lying at the base of a or a very steep rock slope. Large quantities tend to accumulate on the slopes of high by falling, rolling, or sliding from an eroding rockfall source. Compare.

talweg: See.

tank: A small man-made or created by impounding a stream or by constructing a pit or basin to collect and hold rainwater or snowmelt. Less commonly, the term may also refer to a natural pond or basin.

tarn:

A mountain or pool of water formed in a excavated by a. A may form a natural  below a tarn.

temperate zone: Traditionally, either of the two mid-latitude regions of the Earth defined by their position between the and the, i.e. the region between latitudes  and, or that between  and. In modern usage, the term may refer instead to regions of mild or temperate climate, regardless of latitude.

temperature inversion: An increase in temperature with height above the Earth's surface, a reversal of the normal pattern, often observed in deep and that are mostly or entirely enclosed by high.

tephra: Solid material of all sizes explosively ejected from a into the atmosphere.

terminal moraine:

A that forms at the terminus or of a, marking its furthest advance. Debris transported by 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.

terracette: One of a series of regularly spaced, horizontal, step-like forming a distinctive ribbed pattern on a steep and usually grassy hillside, similar to an agricultural or lynchet but naturally occurring. Various explanations for their origins have been suggested, including,, and animal trampling.

terrain:

The vertical and horizontal dimensions of a land surface, usually as expressed in terms of,, and orientation of geographical features.

terrestrial: 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. On, of, or relating to the Earth, as opposed to other planets or to celestial phenomena occurring outside the Earth's atmosphere.

territorial waters: A concept of the Law of the Sea defined as the belt of waters extending no more than 12 nmi from a designated (usually defined as the ) for a coastal  and regarded as the sovereign  of the state; or more generally any area of water over which a state has legal jurisdiction, including, the, and potentially others.

territory: A specific area or portion of the Earth's surface, especially one claimed or administered by a particular country; similar to though distinct from a.

tertiary sector: That portion of a region's economy devoted to service activities (e.g., retail and wholesale operations, transportation, insurance).

thalweg:

The line of lowest within a or, 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 in because disputed  along rivers are often defined by the river's thalweg. This has sometimes led to conflict because the thalweg may change naturally over time.

thaw lake: A shallow, rounded or occupying a  resulting from the melting of ground ice or, ubiquitous in  regions wherever there are flat  with silty  and high ice content, including much of the North American and Siberian. Many thaw lakes develop elongate shapes oriented with the long axis at a right angle to the prevailing wind.

theodolite: An optical instrument consisting of a small telescope, a, and graduated arcs mounted on a tripod, used in and other applications to precisely measure angles between designated visible points in the horizontal and vertical planes.

thermal spring: See.

thermal stratification: The tendency of bodies of water such as 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 at latitudes during the summer, which often form a warm, turbulent  near the surface; a colder, denser ; and a  of  in between. In all but the deepest lakes and oceans, these layers often disappear entirely in the spring and fall, when convective mixing makes the temperature more or less uniform at all depths, and may even invert if the surface freezes during the winter. Local, wind patterns, and dissolved solutes also strongly influence the formation and disruption of stratified waters.

thermocline: A thin layer of water in an ocean or lake, typically between the non-circulating and the warmer, 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-change per metre of descent.

thermokarst: A type of characterized by expansive landscapes of small interspersed with irregular,   formed by the thawing of ice-rich. The unique landforms of thermokarst, including,, , , and linear and polygonal , result from various and thermo-erosional phenomena common in the Arctic and on a smaller scale in mountainous areas such as the Himalayas and the Alps.

tholoid: A occurring inside of a larger volcanic crater or.

throw: The vertical displacement of strata or rocks across the line of a, varying from a few millimetres to hundreds of metres in height. Those rocks on the higher side of the fault are termed upthrow, while those on the lower side are termed downthrow.

tidal creek:

tidal flat: 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 the.

tidal prism: The total volume of water that flows in and out of a coastal or with each cycle of the, excluding any freshwater discharges; i.e. the difference in the inlet's volume between the  and  tides.

tidal range: The difference in height between and at a given location. This range may vary over the course of the year, e.g. during and.

tide: The periodic rise and fall of caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the Earth's rotation.

tide pool: A shallow pool of, supplied regularly by incoming, that forms on a rocky intertidal.

tied island:

An that is connected to a only by a narrow  or  which may or may not be occasionally submerged.

till: See.

timberline: See.

time distance: 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?).

time geography:

An interdisciplinary perspective, ontological framework, and visual language in which space and time are used as basic dimensions of analysis of dynamic processes and events, including social and ecological interactions, environmental changes, and biographies of individuals.

time zone: A region of the globe that observes a uniform standard time for legal, commercial, and social purposes. Most time zones span about 15 degrees of longitude, and in each of these divisions the mean solar time at an arbitrarily selected (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.

Tissot's indicatrix:

A mathematical contrivance used to illustrate the linear, angular, and areal distortions that result when information from a curved three-dimensional geometric model such as a onto a two-dimensional. 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 of and.

toe: See.

toeslope:

toll road:

A public or private road or for which a fee or toll is charged to drivers for passage.

tombolo: A sandy or shingle-covered,, or connecting an to the  or to another island (thereby forming a ).

topocide:

topographic isolation: The minimum between the of a  or  and a point of equal, representing a radius of dominance in which the summit is the highest point.

topographic map:

A that uses to represent the three-dimensional features of a landscape on a two-dimensional surface.

topographic prominence:

A measure of the independence of a or defined as the vertical distance between its  and the lowest  completely encircling it but containing no higher summit within it; or, equivalently, the difference between the  of the summit and the elevation of the. Mountains with high prominence tend to be the highest points in their vicinity.

topographical relief: See.

topography: The physical features of a place, or the study and depiction of physical features, both natural and man-made, including.

topological map: A type of diagrammatic which depicts the actual positional relationships between certain features but on which true 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).

topology: In geographical studies, a discipline concerned with the mathematical analysis of enclosure, order, connectivity,, and relative position rather than with actual distance and orientation. Topological relationships are commonly expressed in terms of networks and depicted with.

toponymy: The study of placenames (known as toponyms), their origins, meanings, use, and typology.

tor:

A prominent, free-standing rock that rises abruptly from the smooth slopes of a gently rounded or. In the United Kingdom, the term is also used to refer to the hill itself.

town: A medium-sized human that is generally larger than a but smaller than a, though the criteria for distinguishing a town vary considerably in different parts of the world.

township and range: 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 the Land Ordinance of 1785.

towpath: A road or path alongside a navigable,, or other inland waterway designed to allow land vehicles, draught animals, or a team of human pullers to tow a boat or barge.

trafficability: The capacity of a soil or of a particular type of terrain to permit the movement of vehicles or pedestrians.

trail:

transferability: The extent to which a good or service can be moved from one location to another; the relative capacity for spatial interaction.

transhumance: The seasonal movement of people and animals in search of pasture. Commonly, winters are spent in snow-free lowlands and summers in the cooler uplands.

transverse: Crosswise; lying across; crossing from one side to another, as a line on a map.

transverse coast: See.

transverse dune: A with its crest oriented at right angles to the direction of the prevailing wind, as opposed to the orientation of a.

transverse valley: A which cuts across a or  at right angles to the primary orientation of the crest. Contrast.

trap street: In, a misrepresented or nonexistent road or street that is deliberately included on a (often outside the map's nominal area of coverage) for the purpose of detecting plagiarism by acting as a copyright 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 and, 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.

traverse: In, a line or 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. A relatively horizontal route taken so as to bypass obstacles when the primary goal is to move vertically, as in rock climbing and mountaineering.

tree line:

The or limit of normal tree growth. Beyond this limit (i.e. closer to the or at higher elevations) climatic conditions are too severe for such growth and trees are stunted or entirely absent. The term cold timberline may also be used to emphasize that the limiting factor is temperature, particularly when distinguishing it from the of arid regions, where tree growth is instead limited by the availability of water.

triangulation: 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 from, which measures distances to the point directly instead of angles.

tributary:

A or that flows into a larger stream or  or a, rather than directly into a  or. Contrast.

trilateration:

tropic: Either of the two of latitude marking the boundary of the : the and the.

Tropic of Cancer: The northernmost on the Earth at which the Sun appears at its culmination, which lies approximately 23.4 degrees north of the. Its southern equivalent is the.

Tropic of Capricorn: The southernmost on the Earth at which the Sun appears at its culmination, which lies approximately 23.4 degrees south of the. Its northern equivalent is the.

tropical: Characteristic of, located in, or relating to the, either the specific parallels of latitude or the zone lying between those two parallels.

tropics:

The region of the Earth's surface surrounding the and bounded by the (23.4° N latitude) and the  (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. See also ' and '.

trough: Any elongated, generally U-shaped,, , or trench, natural or artificial, dry or wet. Particularly common usages refer to a submarine trench or in the, or to a geological.

true north:

The direction along the Earth's surface towards the. Geodetic true north differs from and, and also very slightly from astronomical true north, which is based on the direction of the north.

true south:

The direction along the Earth's surface that is exactly opposite (i.e. bearing 180 degrees) of, towards the.

trunk: See.

tundra: A treeless characteristic of the and subarctic regions.

tunnel valley:

turlough: In western Ireland, a or which fills with water when the  rises, e.g. by tidal effects.

turnpike: See.

tuya:

U
umland: An area which is culturally, economically, and politically related to a particular town or city.

underfit stream: A 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. Contrast.

underpopulation: Economically, a situation in which an increase in the size of the labor force will result in an increase in per-worker productivity.

uniform region: A territory with one or more features present throughout which are absent or unimportant elsewhere.

uninverted relief: Topographic surface which closely reflects the shape and orientation of the underlying geological structure, i.e. where hills and ridges coincide with and valleys with. Contrast.

Universal Transverse Mercator (UTM):

upland:

Any area of land that is higher in relative to another area, especially one that is populated by low or situated atop a. The term is often used as a conditional descriptor to distinguish related habitats or ecosystems, especially freshwater, on the basis of elevation above sea level. Upland areas are usually characterized by relatively fast-flowing waterways and hilly or rocky terrain. Contrast.

upstate:

urban: An adjective describing a settlement with a high and a developed of ; places of this type are variously categorized as,, or , or simply called urban areas. Contrast ', ', and.

urban geography: The sub-discipline of geography that derives from the study of, processes, and the.

urban sprawl: The unrestricted growth of housing, commercial development, and roads (typically of low densities) over large expanses of land, usually within or near an existing or area and with little concern for civic planning. It is often considered a type of and almost always carries negative connotations.

urban studies: The study of the development of and areas, especially from historical, architectural, or civic planning perspectives.

urbanization: The process by which a human shifts from to  residency, the gradual increase in the proportion of people living in urban areas such as  and, 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.

V
vale: Another name for a.

valley: A low area between or, often with a running through it. A that is longer than it is wide.

veld: See.

vent: An opening at the Earth's surface through which volcanic materials (, tephra, and gases) erupt. Vents can be at a 's summit or on its slopes; they can be circular or linear.

vertical exaggeration: A used in certain, such as, that deliberately distorts the apparent of the map's  to emphasize vertical features, which might otherwise appear too small to identify relative to the corresponding horizontal scale.

viewshed: The geographical area that is visible from a particular location. It includes all surrounding points within line-of-sight of the location and excludes points beyond the or obstructed by and natural or artificial objects.

village: A small, clustered human or community, usually larger than a but smaller than a  and often in  areas, though the criteria for distinguishing a village can vary considerably in different parts of the world.

virtual globe: 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 surface of the Earth, such as land use statistics, meteorological records, and demographic quantities. An example is Google Earth.

volcanic avalanche:

A large, chaotic mass of soil, rock, and volcanic debris moving swiftly down the slopes of a volcano. Volcanic avalanches can also occur without an eruption due to an earthquake, heavy rainfall, or unstable soil, rock, and volcanic debris.

volcanic crater: A type of created by activity, typically shaped like a bowl and containing one or more. Compare.

volcano: A vent or opening in the Earth's surface through which magma erupts, or the landform that is constructed by the eruptive material.

volcanology:

vrtače: See.

W
wadi: A dry, ephemeral which contains water only when heavy rainfall occurs. Another name for a, used primarily in Arabic-speaking parts of the world.

warping: The slow, gentle deformation of the Earth's over a wide area, resulting in a raising or lowering of the surface. (sedimentation) Any process, natural or artificial, whereby the low-lying land of a tidal is flooded, leading to of silt, mud, or clay.

wash: The surging movement of the sea or any other large body of water; another name for the of a breaking wave. An area of sand and mud submerged or wettened during and exposed during. A dry or ; an. The collection of fine, granular material that is moved down a slope by erosional processes. See also.

wash margin:

wash slope: See.

washland:

waste land:

Wild, uncultivated, uninhabited land, especially that which is barren or desolate, supporting little or no plant and animal life, such as is found in some. Land that yields little or no return when used for agriculture. Any land, or otherwise, that was previously cultivated or developed but is now abandoned, and for which further use has yet to be found. See also.

water column: In and, a conceptual column of water extending from the surface of an, , or to the sediment of the  or , used to aid interpretation of properties and processes that vary along a depth gradient.

water gap: A low point or opening in a or carved by the erosional activity of flowing water and through which water continues to flow in the present day. Contrast.

water mapping:

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.

water pollution: The contamination of water by chemical or biological constituents which make it unfit for use.

water table: The level below the land surface at which subsurface material such as permeable rock is fully saturated with water. Where the water table is below the land surface, its depth reflects the minimum level to which wells must be drilled for extraction; a occurs where it reaches the land surface, and a permanent  or  results where the theoretical water table is above the land surface. The level of the water table is the boundary between the and the. Its depth fluctuates seasonally, which accounts for the intermittent flow of. In some circumstances, there may be no regular water table; in others, a may exist.

water-meadow: A low-lying area of beside a natural stream or river, subjected to periodic flooding through controlled irrigation to increase agricultural productivity, typically via a series of man-made or drains connected to the stream or river.

waterbody: See.

watercourse: Any followed by a flowing such as a  or, potentially including channels that are dry for part or all of the year.

waterfall:

An abrupt and steep or perpendicular descent in a, e.g. in the of a, 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 a, or by the steep rock faces of a , coastal , or any other or. They may be permanent or ephemeral; many alpine waterfalls form seasonally on mountainsides as snow and ice melts during the summer.

waterhole:

A hollow or in the ground, natural or artificial, in which water can collect, either from precipitation or fed by a, especially in or  where water is otherwise scarce; or a pool in the  of an. Waterholes may be permanent or ephemeral.

watershed: Another name for a, or for the entire catchment area of a.

waterway: Any that is deep, wide, and slow enough to be navigable by watercraft.

wave-cut platform:

A flat erosion surface along the of a lake,, or that is formed by the undercutting and eventual collapse of a  as a result of repetitive wave action.

weathering: The breaking of rocks into smaller rocks, gradually becoming soil.

weir:

A man-made obstruction built across the width of a 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 or flow, typically for navigation, irrigation, fishing, to generate a head for a water mill, or to control outflow from a  or. Compare ' and '.

welfare geography: An approach in 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.

well: 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 natural and remain filled with water up to the level of the, 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. An taps a water source held under considerable pressure.

Western Hemisphere: The of the Earth that is west of the and east of the, and opposite the. The Western Hemisphere includes all of the Americas, the Atlantic Ocean, and a large portion of the Pacific Ocean.

wetland: Any area of land or, natural or artificial, which is flooded or saturated by water, either seasonally or intermittently for short periods or permanently for years or decades, and characterized generally by oxygen-poor hydric soils, distinct flora, high, and interactions between terrestrial and aquatic processes. Wetlands may be, , or ecosystems, and are often classified based on their sources of water (as with , , , , and ) and/or their dominant vegetation (as with and ).

wilderness: Any natural environment which has not been significantly developed or modified by human activity, or within which natural processes operate without human interference. Such areas are considered important for the survival of wild plant and animal species as well as for maintaining and ecological stability. Wildernesses are often.

wind gap:

A, notch, or opening in a or, originally carved by a watercourse flowing through it but which is now dry as a result of. Contrast.

wind rose: See.

windward: The side of a landmass facing the direction from which the wind is blowing. Contrast.

winterbourne:

An intermittent stream or which is dry during the summer, especially one formed in the downlands of southern England.

witness hill:

world:

world city: See.

World Geodetic System (WGS): A standard, spheroidal (for raw data), and  (which defines the nominal ) used in, , and  applications worldwide. The latest revision, WGS84, is the standard coordinate system used by the.

world map: A of most or all of the surface of the Earth.

worldwide: See.

Z
zeuge: A tabular mass of rock that has become perched atop a pinnacle created by erosion (often ) of the softer, underlying rock. See also ', ', and.

zibar: A type of low with limited development, often occurring in the corridors between higher dunes.

zonation: In and ecology, the separation of the Earth's flora and fauna into distinct groups occupying characteristic habitats,,, or other idealized geographic divisions, primarily defined by climate, for the purpose of identifying and categorizing patterns in biodiversity. 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.

zoning: The public regulation of land and building use to control the character of a place.

zenith: The imaginary point on the celestial sphere that is directly above a particular location (i.e. in the vertical direction exactly opposite to the apparent direction of the gravitational force at that location). Contrast.