r.param.scale - Extracts terrain parameters from a DEM. Uses a multi-scale approach by taking fitting quadratic parameters to any size window (via least squares).
raster, geomorphology, terrain, elevation, landform
r.param.scale r.param.scale --help r.param.scale [-c] input=name output=name [slope_tolerance=float] [curvature_tolerance=float] [size=integer] [method=string] [exponent=float] [zscale=float] [--overwrite] [--help] [--verbose] [--quiet] [--ui] Flags: -c Constrain model through central window cell --overwrite Allow output files to overwrite existing files --help Print usage summary --verbose Verbose module output --quiet Quiet module output --ui Force launching GUI dialog Parameters: input=name [required] Name of input raster map output=name [required] Name for output raster map containing morphometric parameter slope_tolerance=float Slope tolerance that defines a 'flat' surface (degrees) Default: 1.0 curvature_tolerance=float Curvature tolerance that defines 'planar' surface Default: 0.0001 size=integer Size of processing window (odd number only) Options: 3-499 Default: 3 method=string Morphometric parameter in 'size' window to calculate Options: elev, slope, aspect, profc, planc, longc, crosc, minic, maxic, feature Default: elev exponent=float Exponent for distance weighting (0.0-4.0) Default: 0.0 zscale=float Vertical scaling factor Default: 1.0
r.param.scale extracts terrain parameters from a digital elevation model. Uses a multi-scale approach by fitting a bivariate quadratic polynomial to a given window size using least squares. The module calculates the following parameters (terminology is from Wood, 1996 with related terminology used in other GRASS modules listed in brackets): * elev: Generalised elevation value (for resampling purposes at different scale) * slope: Magnitude of maximum gradient (steepest slope angle) * aspect: Direction of maximum gradient (steepest slope direction=flow direction) * profc: profile curvature (curvature intersecting with the plane defined by Z axis and maximum gradient direction). Positive values describe convex profile curvature, negative values concave profile curvature. * planc: plan curvature (horizontal curvature, intersecting with the XY plane) * longc: longitudinal curvature (profile curvature intersecting with the plane defined by the surface normal and maximum gradient direction) * crosc: cross-sectional curvature (tangential curvature intersecting with the plane defined by the surface normal and a tangent to the contour - perpendicular to maximum gradient direction) * maxic: maximum curvature (can be in any direction) * minic: minimum curvature (in direction perpendicular to the direction of of maximum curvature) * feature: Morphometric features: peaks, ridges, passes, channels, pits and planes
In r.param.scale the direction of maximum gradient (considered downslope) is stored as (West is 0 degree, East is +/- 180 degree): * 0..+180 degree from West to North to East * 0..-180 degree from West to South to East Note that the aspect map is calculated differently from r.slope.aspect.
The next commands will create a geomorphological map of the Spearfish sample dataset region: g.region raster=elevation.10m -p r.param.scale in=elevation.10m output=morphology method=feature size=9 Figure: Geomorphological map of a subregion in the Spearfish (SD) area
Fix bug when `constrain through central cell' option selected. Create color tables for all output files (presently only on features).
* Wood, J. (1996): The Geomorphological characterisation of Digital Elevation Models. Diss., Department of Geography, University of Leicester, U.K online at: http://hdl.handle.net/2381/34503 * Java Code in LandSerf that implements the same procedure
r.slope.aspect
jwo@le.ac.uk - ASSIST's home Update to FP 3/2002: L. Potrich, M. Neteler, S. Menegon (ITC-irst) Last changed: $Date: 2016-12-11 19:03:35 +0100 (Sun, 11 Dec 2016) $
Available at: r.param.scale source code (history) Main index | Raster index | Topics index | Keywords index | Graphical index | Full index 2003-2016 GRASS Development Team, GRASS GIS 7.2.0 Reference Manual
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