1r.shaded.relief(1) Grass User's Manual r.shaded.relief(1)
2
6 r.shaded.relief - Creates shaded relief map from an elevation map
7 (DEM).
8
10 raster, elevation
11
13 r.shaded.relief
14 r.shaded.relief help
15 r.shaded.relief map=string [shadedmap=string] [altitude=integer]
16 [azimuth=integer] [zmult=float] [scale=float] [units=string]
17 [--overwrite]
18 Flags:
20 --overwrite
21 Parameters:
23 map=string
24 Input elevation map
25 shadedmap=string
27 Output shaded relief map name
28 altitude=integer
30 Altitude of the sun in degrees above the horizon Options: 0-90
31 Default: 30
32 azimuth=integer
34 Azimuth of the sun in degrees to the east of north Options: 0-360
35 Default: 270
36 zmult=float
38 Factor for exaggerating relief Default: 1
39 scale=float
41 Scale factor for converting horizontal units to elevation units
42 Default: 1
43 units=string
45 Set scaling factor (applies to lat./long. locations only) Options:
46 meters,feet
47
49 r.shaded.relief is a Bourne shell script that creates a raster shaded
50 relief map based on current resolution settings and on sun altitude,
51 azimuth, and z-exaggeration values entered by the user. If no output
52 shademap name is given, the new shaded relief map is named .shade. The
53 map is assigned a grey-scale color table.
54 If no parameters are provided on startup, this program is interactive;
56 thus if the user enters the command: r.shaded.relief
57 The program then prompts the user to enter values for: The altitude of
59 the sun in degrees above the horizon (a value between 0 and 90
60 degrees), and The azimuth of the sun in degrees to the east of north (a
61 value between 0 and 360 degrees). The name of a raster map layer to
62 provide elevation values for the shaded relief map. Typically, this
63 would be a map layer of elevation; however, any raster map layer can be
64 named. The scaling parameter, which compensates for a different hori‐
65 zontal scale than vertical scale. If 'scale' is a number then the ewres
66 and nsres are multiplied by that scale to calculate the shading.
67 (Default=1.0 for equivalent horizontal and vertical scales.)
68 For ETOPO2 data a scale factor of 10000 generates an acceptable shading
69 effect. For the special case when a latitude-longitude projection is
70 used with an elevation map measured in meters or feet, the units can be
71 set to automatically set the horizontal scale to the the number of
72 meters or feet in a degree of latitude. The script scales latitude and
73 longitude equally, so it's only approximately right, but for shading
74 it's close enough. It makes the difference between a usable and unus‐
75 able shade. The zmult exaggeration factor that changes the apparent
76 relief for the shaded relief map. This can be any positive (or nega‐
77 tive) floating point value. (Default=1.0)
78 Specifically, r.shaded.relief executes a r.mapcalc statement. Refer to
80 the manual entry for r.mapcalc for an explanation of the filtering syn‐
81 tax shown in the above expression. See, for example, the section on
82 "The Neighborhood Modifier".
83 r.shaded.relief then runs r.colors to assign a grey-scale color table
85 to the new shaded relief map.
86
88 This program is simply a shell script. Users are encouraged to make
89 their own shell scripts using similar techniques. See $GIS‐
90 BASE/scripts/r.shaded.relief.
91
93 An Algebra for GIS and Image Processing, by Michael Shapiro and Jim
94 Westervelt, U.S. Army Construction Engineering Research Laboratory
95 (March/1991) (get from GRASS web site).
96 d.his
98 g.region
99 r.blend
100 r.colors
101 r.mapcalc
102
104 Jim Westervelt, U.S. Army Construction Engineering Research Laboratory
105 Last changed: $Date: 2006/04/20 02:43:23 $
107 Full index
109GRASS 6.2.2 r.shaded.relief(1)