Principles

en    ru

###### Principles of geomorphometric modelling

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 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.

For details and examples, see:

 DIGITAL TERRAIN ANALYSIS IN SOIL SCIENCE AND GEOLOGY   2nd revised edition     I.V. Florinsky   Elsevier / Academic Press, 2016 Amsterdam, 486 p.   ISBN 978-0-12-804632-6