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Topography is a
base of landscape and one of
the main factors controlling processes taking place in the near-surface
layer of the planet.
Digital terrain modelling (geomorphometry) is a science of
quantitative modelling and analysis of the topographic surface and
relationships between topography and other natural and artificial
components of geosystems. Digital
terrain modelling is
widely used to solve various multiscale problems of geomorphology,
hydrology, soil science, geobotany, geology, glaciology, oceanology,
climatology, and other disciplines.
Digital elevation models (DEMs), two-dimensional discrete functions
of elevation, are the main source of information on topography. DEMs are
used to calculate digital
terrain models (DTMs), two-dimensional
discrete functions of morphometric variables.
· Local morphometric variables (describing the geometry of the topographic surface in the
vicinity of a given point on the surface):
- Slope gradient
- Slope aspect
- Horizontal curvature
- Vertical
curvature
- Minimal
curvature
- Maximal curvature
- Mean
curvature
- Difference curvature
- Gaussian
curvature
- Horizontal excess curvature
- Vertical excess curvature
- Accumulation curvature
- Ring
curvature
- Unsphericity curvature
- Rotor
· Nonlocal morphometric variables (describing a relative position of a given point on the
topographic surface):
- Catchment area
- Dispersive area
· Solar morphometric variables (describing relations between the
topographic surface and solar irradiation in the vicinity of a given point
of the topographic surface):
- Reflectance
- Insolation
· Combined morphometric variables (considering both the local geometry of the topographic
surface and a relative position of a point on the surface):
- Topographic index
- Stream power index
Being a morphometric variable, elevation does not belong to any type. All other
morphometric variables are derived from DEMs.
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