Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, structurestratification, rock exposure, and soil type. Gross physical features or landforms include intuitive elements such asberms,cliffs,hills,mounds,peninsulas,ridges,rivers,valleys,volcanoes, and numerous other structural and size-scaled (e.g.ponds vs.lakes,hills vs.mountains) elements including various kinds of inland and oceanicwaterbodies and sub-surface features. Hills, mountains,plains, andplateaus are the four major types of landforms on Earth. Minor landforms include basins,buttes, canyons, and valleys. Tectonic plate movements under Earth's crust can create landforms by pushing up hills and mountains.
Continents andoceans exemplify the highest-order landforms.[citation needed]Landform elements are parts of a high-order landforms that can be further identified and systematically given a cohesive definition such as hill-tops, shoulders,saddles, foreslopes and backslopes.
Some generic landform elements including: pits, peaks, channels, ridges, passes, pools and plains.
Elementary landforms (segments, facets, relief units) are the smallest homogeneous divisions of the land surface, at the given scale/resolution. These are areas with relatively homogeneousmorphometric properties, bounded by lines of discontinuity. A plateau or a hill can be observed at various scales, ranging from a few hundred meters to hundreds of kilometers. Hence, the spatial distribution of landforms is often scale-dependent, as is the case for soils and geological strata.
Landforms do not include several man-made features, such ascanals,ports and manyharbors; and geographic features, such asdeserts,forests, andgrasslands. Many of the terms are not restricted to refer to features of the planetEarth, and can be used to describe surface features of other planets and similar objects in theUniverse. Examples are mountains, hills, polar caps, and valleys, which are found on all of theterrestrial planets.
The scientific study of landforms is known asgeomorphology.
Inonomastic terminology,toponyms (geographical proper names) of individual landform objects (mountains, hills, valleys, etc.) are calledoronyms.[4]
Landforms may be extracted from adigital elevation model (DEM) using some automated techniques where the data has been gathered by modern satellites andstereoscopicaerial surveillance cameras.[5] Until recently, compiling the data found in such data sets required time consuming and expensive techniques involving many man-hours. The most detailed DEMs available are measured directly usingLIDAR techniques.
