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:
- Slope gradient
- Slope aspect
- Horizontal curvature
- Difference curvature
- Horizontal excess curvature
- Vertical excess curvature
- Accumulation curvature
- Unsphericity curvature
· Nonlocal morphometric variables:
- Catchment area
- Dispersive area
· Solar morphometric variables:
· Combined morphometric variables:
- Topographic index
- Stream power index
Being a morphometric variable, elevation does not belong to any type. All other
morphometric variables are derived from DEMs.