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Slope
gradient is an angle between the tangential
and horizontal planes at a given point of the topographic surface*. The
unit of measurement is degree. Once elevations are given by , where x
and y are plane Cartesian co-ordinates, slope gradient is a function
of the partial derivatives of z: , where and . Slope
gradient determines the velocity of gravity-driven flows. Like
other local morphometric variables, slope
gradient can be derived from a digital
elevation model (DEM) by finite-difference methods (e.g., IF-2009 method and IF-1998 method) as well as the universal spectral
analytical method. Example**. A model of slope gradient was derived from a
DEM of Mount Ararat by the
universal spectral analytical method.
The model includes 779,401 points
(the matrix 1081 x 721); the grid spacing is 1". The vertical
exaggeration of the 3D model is 2x. The data processing and modelling were carried out using the software Matlab R2008b. References
*
Shary, P.A., 1995. Land surface in gravity points classification by a
complete system of curvatures. Mathematical Geology, 27: 373–390.
** Florinsky,
I.V., 2017. An illustrated introduction to
general geomorphometry. Progress in Physical Geography, 41:
723–752. doi pdf
For
details and other examples, see:
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