Topography is a
base of landscape and one of
the main factors controlling processes taking place in the nearsurface
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), twodimensional discrete functions
of elevation, are the main source of information on topography. DEMs are
used to calculate digital
terrain models (DTMs), twodimensional
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.
