1r.param.scale(1) GRASS GIS User's Manual r.param.scale(1)
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6 r.param.scale - Extracts terrain parameters from a DEM.
7 Uses a multi-scale approach by taking fitting quadratic parameters to
8 any size window (via least squares).
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11 raster, geomorphology, terrain, elevation, landform
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14 r.param.scale
15 r.param.scale --help
16 r.param.scale [-c] input=name output=name [slope_tolerance=float]
17 [curvature_tolerance=float] [size=integer] [method=string] [expo‐
18 nent=float] [zscale=float] [--overwrite] [--help] [--verbose]
19 [--quiet] [--ui]
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21 Flags:
22 -c
23 Constrain model through central window cell
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25 --overwrite
26 Allow output files to overwrite existing files
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28 --help
29 Print usage summary
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31 --verbose
32 Verbose module output
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34 --quiet
35 Quiet module output
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37 --ui
38 Force launching GUI dialog
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40 Parameters:
41 input=name [required]
42 Name of input raster map
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44 output=name [required]
45 Name for output raster map containing morphometric parameter
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47 slope_tolerance=float
48 Slope tolerance that defines a ’flat’ surface (degrees)
49 Default: 1.0
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51 curvature_tolerance=float
52 Curvature tolerance that defines ’planar’ surface
53 Default: 0.0001
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55 size=integer
56 Size of processing window (odd number only)
57 Options: 3-499
58 Default: 3
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60 method=string
61 Morphometric parameter in ’size’ window to calculate
62 Options: elev, slope, aspect, profc, planc, longc, crosc, minic,
63 maxic, feature
64 Default: elev
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66 exponent=float
67 Exponent for distance weighting (0.0-4.0)
68 Default: 0.0
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70 zscale=float
71 Vertical scaling factor
72 Default: 1.0
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75 r.param.scale extracts terrain parameters from a digital elevation
76 model. Uses a multi-scale approach by fitting a bivariate quadratic
77 polynomial to a given window size using least squares.
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79 The module calculates the following parameters (terminology is from
80 Wood, 1996 with related terminology used in other GRASS modules listed
81 in brackets):
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83 • elev: Generalised elevation value (for resampling purposes at
84 different scale)
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86 • slope: Magnitude of maximum gradient (steepest slope angle)
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88 • aspect: Direction of maximum gradient (steepest slope direc‐
89 tion=flow direction)
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91 • profc: profile curvature (curvature intersecting with the plane
92 defined by Z axis and maximum gradient direction). Positive
93 values describe convex profile curvature, negative values con‐
94 cave profile curvature.
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96 • planc: plan curvature (horizontal curvature, intersecting with
97 the XY plane)
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99 • longc: longitudinal curvature (profile curvature intersecting
100 with the plane defined by the surface normal and maximum gradi‐
101 ent direction)
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103 • crosc: cross-sectional curvature (tangential curvature inter‐
104 secting with the plane defined by the surface normal and a tan‐
105 gent to the contour - perpendicular to maximum gradient direc‐
106 tion)
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108 • maxic: maximum curvature (can be in any direction)
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110 • minic: minimum curvature (in direction perpendicular to the di‐
111 rection of of maximum curvature)
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113 • feature: Morphometric features: peaks, ridges, passes, chan‐
114 nels, pits and planes
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117 In r.param.scale the direction of maximum gradient (considered downs‐
118 lope) is stored as (West is 0 degree, East is +/- 180 degree):
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120 • 0..+180 degree from West to North to East
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122 • 0..-180 degree from West to South to East
123 Note that the aspect map is calculated differently from r.slope.aspect.
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126 The next commands will create a geomorphological map of the Spearfish
127 sample dataset region:
128 g.region raster=elevation.10m -p
129 r.param.scale in=elevation.10m output=morphology method=feature size=9
130 Figure: Geomorphological map of a subregion in the Spearfish (SD) area
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133 Fix bug when `constrain through central cell’ option selected. Create
134 color tables for all output files (presently only on features).
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137 • Wood, J. (1996): The Geomorphological characterisation of Digi‐
138 tal Elevation Models. Diss., Department of Geography, Univer‐
139 sity of Leicester, U.K
140 online at: http://hdl.handle.net/2381/34503
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142 • Java Code in LandSerf that implements the same procedure
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145 r.geomorphon, r.slope.aspect
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148 Jo Wood - ASSIST’s home
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150 Update to FP 3/2002: L. Potrich, M. Neteler, S. Menegon (ITC-irst)
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153 Available at: r.param.scale source code (history)
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155 Accessed: Saturday Jan 21 20:38:53 2023
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160 © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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164GRASS 8.2.1 r.param.scale(1)