r.param.scale(1)

1r.param.scale(1)              Grass User's Manual             r.param.scale(1)
2
3
4

NAME

6       r.param.scale   - Extracts terrain parameters from a DEM. Uses a multi-
7       scalar approach by taking fitting quadratic parameters to any size win‐
8       dow (via least squares)
9

KEYWORDS

11       raster
12

SYNOPSIS

14       r.param.scale
15       r.param.scale help
16       r.param.scale     [-c]     input=name     output=name     [s_tol=float]
17       [c_tol=float]      [size=integer]      [param=string]       [exp=float]
18       [zscale=float]   [--overwrite]
19
20   Flags:
21       -c  Constrain model through central window cell
22
23       --overwrite
24
25   Parameters:
26       input=name
27           Name of input raster map
28
29       output=name
30           Output raster layer containing morphometric parameter
31
32       s_tol=float
33           Slope  tolerance  that  defines a 'flat' surface (degrees) Default:
34           1.0
35
36       c_tol=float
37           Curvature tolerance that defines 'planar' surface Default: 0.0001
38
39       size=integer
40           Size of processing window (odd number only, max: 69) Default: 3
41
42       param=string
43           Morphometric parameter  in  'size'  window  to  calculate  Options:
44           elev,slope,aspect,profc,planc,longc,crosc,minic,maxic,feature
45           Default: elev
46
47       exp=float
48           Exponent for distance weighting (0.0-4.0) Default: 0.0
49
50       zscale=float
51           Vertical scaling factor Default: 1.0
52

DESCRIPTION

54       r.param.scale extracts terrain parameters from a  DEM.  Uses  a  multi-
55       scale  approach  by fitting a bivariate quadratic polynomial to a given
56       window size using least squares.
57
58       The module calculates the following  parameters  (terminology  is  from
59       Wood,  1996 with related terminology used in other GRASS modules listed
60       in brackets):
61
62                     elev: Generalised elevation value  (for  resampling  pur‐
63                     poses at different scale)
64
65                     slope:  Magnitude  of  maximum  gradient  (steepest slope
66                     angle)
67
68                     aspect: Direction of  maximum  gradient  (steepest  slope
69                     direction=flow direction)
70
71                     profc  or  profile curvature (curvature intersecting with
72                     the plane defined by Z axis and maximum  gradient  direc‐
73                     tion). Positive values describe convex profile curvature,
74                     negative values concave profile curvature.
75
76                     planc or plan curvature (horizontal curvature, intersect‐
77                     ing with the XY plane)
78
79                     longc or longitudinal curvature (profile curvature inter‐
80                     secting with the plane defined by the surface normal  and
81                     maximum gradient direction)
82
83                     crosc  or cross-sectional curvature (tangential curvature
84                     intersecting with the plane defined by the surface normal
85                     and  a  tangent to the contour - perpendicular to maximum
86                     gradient direction)
87
88                     maxic or maximum curvature (can be in any direction)
89
90                     minic or minimum curvature (in direction perpendicular to
91                     the direction of of maximum curvature)
92
93                     feature:  Morphometric  features:  peaks, ridges, passes,
94                     channels, pits and planes
95

NOTES

97       In r.param.scale the direction of maximum gradient  (considered  downs‐
98       lope) is stored as (West is 0 degree, East is +/- 180 degree):
99
100                     0..+180 degree from West to North to East
101
102                     0..-180 degree from West to South to East
103       Note that the aspect map is calculated differently from r.slope.aspect.
104

Still to do

106       Fix  bug  when `constrain through central cell' option selected. Create
107       color tables for all output files (presently only on features).
108

EXAMPLE

110       The next commands will create a morphology map of the Spearfish region:
111       g.region rast=elevation.10m -p
112       r.param.scale in=elevation.10m output=morphology param=feature
113
114

REFERENCE

119       Wood, J. (1996): The Geomorphological characterisation of Digital  Ele‐
120       vation Models. Diss., Department of Geography, University of Leicester,
121       U.K.
122       online at:
123       http://www.soi.city.ac.uk/~jwo/phd/
124

AUTHOR

126       jwo@le.ac.uk - ASSIST's home
127
128       Update to FP 3/2002: L. Potrich, M. Neteler, S. Menegon (ITC-irst)
129
130       Last changed: $Date: 2006/07/15 18:23:43 $
131
132       Full index
133
134
135
136GRASS 6.2.2                                                   r.param.scale(1)