1r.colors(1) GRASS GIS User's Manual r.colors(1)
2
6 r.colors - Creates/modifies the color table associated with a raster
7 map.
8
10 raster, color table
11
13 r.colors
14 r.colors --help
15 r.colors [-rwldngae] [map=name[,name,...]] [file=name]
16 [color=style] [raster=name] [raster_3d=name] [rules=name]
17 [--help] [--verbose] [--quiet] [--ui]
18 Flags:
20 -r
21 Remove existing color table
22 -w
24 Only write new color table if it does not already exist
25 -l
27 List available rules then exit
28 -d
30 List available rules with description then exit
31 If a color rule is given, only this rule is listed
32 -n
34 Invert colors
35 -g
37 Logarithmic scaling
38 -a
40 Logarithmic-absolute scaling
41 -e
43 Histogram equalization
44 --help
46 Print usage summary
47 --verbose
49 Verbose module output
50 --quiet
52 Quiet module output
53 --ui
55 Force launching GUI dialog
56 Parameters:
58 map=name[,name,...]
59 Name of raster map(s)
60 file=name
62 Input file with one map name per line
63 Input map names can be defined in an input file in case a large
64 amount of maps must be specified. This option is mutual exclusive
65 to the map option.
66 color=style
68 Name of color table
69 Options: aspect, aspectcolr, bcyr, bgyr, blues, byg, byr, celsius,
70 corine, curvature, differences, elevation, etopo2, evi, fahrenheit,
71 forest_cover, gdd, grass, greens, grey, grey.eq, grey.log, grey1.0,
72 grey255, gyr, haxby, inferno, kelvin, magma, ndvi, ndwi, nlcd,
73 oranges, plasma, population, population_dens, precipitation, pre‐
74 cipitation_daily, precipitation_monthly, rainbow, ramp, random,
75 reds, roygbiv, rstcurv, ryb, ryg, sepia, slope, soilmoisture, srtm,
76 srtm_plus, terrain, viridis, water, wave
77 aspect: aspect oriented grey colors [range: map values]
78 aspectcolr: aspect oriented rainbow colors [range: 0 to 360]
79 bcyr: blue through cyan through yellow to red [range: map values]
80 bgyr: blue through green through yellow to red [range: map values]
81 blues: white to blue [range: map values]
82 byg: blue through yellow to green [range: map values]
83 byr: blue through yellow to red [range: map values]
84 celsius: blue to red for degree Celsius temperature [range: -80 to
85 80]
86 corine: EU Corine land cover colors [range: 111 to 995]
87 curvature: for terrain curvatures (from v.surf.rst and
88 r.slope.aspect) [range: map values]
89 differences: differences oriented colors [range: map values]
90 elevation: maps relative ranges of raster values to elevation
91 color ramp [range: map values]
92 etopo2: colors for ETOPO2 worldwide bathymetry/topography [range:
93 -11000 to 8850]
94 evi: enhanced vegetative index colors [range: -1 to 1]
95 fahrenheit: blue to red for Fahrenheit temperature [range: -112 to
96 176]
97 forest_cover: percentage of forest cover [range: 0 to 100]
98 gdd: accumulated growing degree days [range: 0 to 6000]
99 grass: GRASS GIS green (perceptually uniform) [range: map values]
100 greens: white to green [range: map values]
101 grey: grey scale [range: map values]
102 grey.eq: histogram-equalized grey scale [range: map values]
103 grey.log: histogram logarithmic transformed grey scale [range: map
104 values]
105 grey1.0: grey scale for raster values between 0.0-1.0 [range: 0 to
106 1]
107 grey255: grey scale for raster values between 0-255 [range: 0 to
108 255]
109 gyr: green through yellow to red [range: map values]
110 haxby: relative colors for bathymetry or topography [range: map
111 values]
112 inferno: perceptually uniform sequential color table inferno
113 [range: map values]
114 kelvin: blue to red for temperature in Kelvin scale [range: 193.15
115 to 353.15]
116 magma: perceptually uniform sequential color table magma [range:
117 map values]
118 ndvi: Normalized Difference Vegetation Index colors [range: -1 to
119 1]
120 ndwi: Normalized Difference Water Index colors [range: -200 to
121 200]
122 nlcd: US National Land Cover Dataset colors [range: 0 to 95]
123 oranges: white to orange [range: map values]
124 plasma: perceptually uniform sequential color table plasma [range:
125 map values]
126 population: color table covering human population classification
127 breaks [range: 0 to 2e+09]
128 population_dens: color table covering human population density
129 classification breaks [range: 0 to 1e+09]
130 precipitation: precipitation color table (0..2000mm) [range: 0 to
131 7000]
132 precipitation_daily: precipitation color table (0..1000mm) [range:
133 0 to 10000]
134 precipitation_monthly: precipitation color table (0..1000mm)
135 [range: 0 to 1000]
136 rainbow: rainbow color table [range: map values]
137 ramp: color ramp [range: map values]
138 random: random color table [range: map values]
139 reds: white to red [range: map values]
140 roygbiv: [range: map values]
141 rstcurv: terrain curvature (from r.resamp.rst) [range: map values]
142 ryb: red through yellow to blue [range: map values]
143 ryg: red through yellow to green [range: map values]
144 sepia: yellowish-brown through to white [range: map values]
145 slope: r.slope.aspect-type slope colors for raster values 0-90
146 [range: 0 to 90]
147 soilmoisture: soilmoisture color table (0.0-1.0) [range: 0 to 1]
148 srtm: color palette for Shuttle Radar Topography Mission elevation
149 [range: -11000 to 8850]
150 srtm_plus: color palette for Shuttle Radar Topography Mission ele‐
151 vation (with seafloor colors) [range: -11000 to 8850]
152 terrain: global elevation color table covering -11000 to +8850m
153 [range: -11000 to 8850]
154 viridis: perceptually uniform sequential color table viridis
155 [range: map values]
156 water: water depth [range: map values]
157 wave: color wave [range: map values]
158 raster=name
160 Raster map from which to copy color table
161 raster_3d=name
163 3D raster map from which to copy color table
164 rules=name
166 Path to rules file
167 "-" to read rules from stdin
168
170 r.colors allows the user to create and/or modify the color table for a
171 raster map or several raster maps at once. The raster maps (specified
172 on the command line by map or as file using an input file with one map
173 name per line) must exist in the user’s current mapset search path.
174 The raster option allows user to specify a raster map name from which
176 to copy the color map.
177 The raster_3d option allows user to specify a 3D raster map name from
179 which to copy the color map.
180 The -e flag equalizes the original raster’s color table. It can pre‐
182 clude the need for grey.eq rule, when used as -e color=grey. Note how‐
183 ever, that this will not yield a color table identical to
184 color=grey.eq, because grey.eq scales the fraction by 256 to get a grey
185 level, while -e uses it to interpolate the original color table. If the
186 original color table is a 0-255 grey scale, -e is effectively scaling
187 the fraction by 255. Different algorithms are used. -e is designed to
188 work with any color table, both the floating point and the integer
189 raster maps.
190 The -g flag divides the raster’s grey value range into 100 logarithmi‐
192 cally equal steps (where "step" is a rule with the same grey level for
193 the start and end points). It can preclude the need for grey.log rule,
194 when used as -g color=grey. Note however, that this will not yield a
195 color table identical to color=grey.log. Different algorithms are used.
196 Unlike color=grey.log, -g is designed to work with both floating point
197 and integer rasters, without performance issues with large datasets, of
198 any original color table. Logarithmic scaling doesn’t work on negative
199 values. In the case when the value range includes zero, there’s no
200 realistic solution.
201 The -e and -g flags are not mutually exclusive.
203 If the user specifies the -w flag, the current color table file for the
205 input map will not be overwritten. This means that the color table is
206 created only if the map does not already have a color table. If this
207 option is not specified, the color table will be created if one does
208 not exist, or modified if it does.
209 Color table types aspect, grey, grey.eq (histogram-equalized grey
211 scale), byg (blue-yellow-green), byr (blue-yellow-red), gyr (green-yel‐
212 low-red), rainbow, ramp, ryg (red-yellow-green), random, and wave are
213 pre-defined color tables that r.colors knows how to create without any
214 further input.
215 In case several input raster maps are provided the range (min, max) of
217 all maps will be used for color table creation. Hence the created color
218 table will span from the smallest minimum to the largest maximum value
219 of all input raster maps and will be applied to all input raster maps.
220 In general, tables which associate colors with percentages (aspect,
222 bcyr, byg, byr, elevation, grey, gyr, rainbow, ramp, ryb, ryg and wave)
223 can be applied to any data, while those which use absolute values
224 (aspectcolr, curvature, etopo2, evi, ndvi, population, slope, srtm, and
225 terrain) only make sense for data with certain ranges. One can get a
226 rough idea of the applicability of a colour table by reading the corre‐
227 sponding rules file ($GISBASE/etc/colors/<name>). For example the
228 slope rule is defined as:
229 0 255:255:255
230 2 255:255:0
231 5 0:255:0
232 10 0:255 255
233 15 0:0:255
234 30 255:0:255
235 50 255:0:0
236 90 0:0:0
237 This is designed for the slope map generated by r.slope.aspect, where
239 the value is a slope angle between 0 and 90 degrees.
240 Similarly, the aspectcolr rule:
242 0 white
243 1 yellow
244 90 green
245 180 cyan
246 270 red
247 360 yellow
248 is designed for the aspect maps produced by r.slope.aspect, where the
250 value is a heading between 0 and 360 degrees.
251 The rules color table type will cause r.colors to read color table
253 specifications from standard input (stdin) and will build the color ta‐
254 ble accordingly.
255 Using color table type rules, there are two ways to build a color ta‐
257 ble: by category values and by "percent" values.
258 To build a color table by category values’ indices, the user should
260 determine the range of category values in the raster map with which the
261 color table will be used. Specific category values will then be associ‐
262 ated with specific colors. Note that a color does not have to be
263 assigned for every valid category value because r.colors will interpo‐
264 late a color ramp to fill in where color specification rules have been
265 left out. The format of such a specification is as follows:
266 category_value color_name
267 category_value color_name
268 .. ..
269 .. ..
270 category_value color_name
271 end
272 Each category value must be valid for the raster map, category values
274 must be in ascending order and only use standard GRASS color names
275 (aqua, black, blue, brown, cyan, gray, green, grey, indigo, magenta,
276 orange, purple, red, violet, white, yellow).
277 Colors can also be specified by color numbers each in the range 0-255.
279 The format of a category value color table specification using color
280 numbers instead of color names is as follows:
281 category_value red_number:green_number:blue_number
282 category_value red_number:green_number:blue_number
283 .. .. .. ..
284 .. .. .. ..
285 category_value red_number:green_number:blue_number
286 end
287 Specifying a color table by "percent" values allows one to treat a
289 color table as if it were numbered from 0 to 100. The format of a "per‐
290 cent" value color table specification is the same as for a category
291 value color specification, except that the category values are replaced
292 by "percent" values, each from 0-100, in ascending order. The format is
293 as follows:
294 percent_value% color_name
295 percent_value% color_name
296 .. ..
297 .. ..
298 percent_value% color_name
299 end
300 Using "percent" value color table specification rules, colors can also
302 be specified by color numbers each in the range 0-255. The format of a
303 percent value color table specification using color numbers instead of
304 color names is as follows:
305 percent_value% red_number:green_number:blue_number
306 percent_value% red_number:green_number:blue_number
307 .. .. .. ..
308 .. .. .. ..
309 percent_value% red_number:green_number:blue_number
310 end
311 Note that you can also mix these two methods of color table specifica‐
313 tion; for example:
314 0 black
315 10% yellow
316 78 blue
317 100% 0:255:230
318 end
319 To set the NULL (no data) color, use the "nv" (null values) parameter:
321 0 black
322 10% yellow
323 nv white
324 end
325 To set the color to used for undefined values (beyond the range of the
327 color rules) use the "default" parameter:
328 0 red
329 1 blue
330 default grey
331 end
332
334 All color tables are stored in $GISBASE/etc/colors/. Further
335 user-defined color tables can also be stored in this directory for
336 access from the color parameter or in a user defined directory. See
337 also r.colors.out for printing color tables easily to the terminal.
338 The color table assigned to a raster map is stored in $GISDBASE/loca‐
340 tion/mapset/colr/.
341
343 The below example shows how you can specify colors for a three category
344 map, assigning red to category 1, green to category 2, and blue to cat‐
345 egory 3. Start by using a text editor to create the following rules
346 specification file (save it with the name rules.file):
347 1 red
348 2 green
349 3 blue
350 end
351 The color table can then by assigned to map threecats by the following
353 GRASS commands (two ways are available):
354 # read input from stdin
355 cat rules.file | r.colors map=threecats rules=-
356 # read directly from file
357 r.colors map=threecats rules=rules.file
358 To create a natural looking lookup table (LUT) for true map layer ele‐
360 vation, use the following rules specification file. It will assign
361 light green shades to the lower elevations (first 20% of the LUT), and
362 then darker greens (next 15%, and next 20%) and light browns (next 20%)
363 for middle elevations, and darker browns (next 15%) for higher eleva‐
364 tions, and finally yellow for the highest peaks (last 10% of LUT).
365 0% 0:230:0
366 20% 0:160:0
367 35% 50:130:0
368 55% 120:100:30
369 75% 120:130:40
370 90% 170:160:50
371 100% 255:255:100
372 To invert the current rules:
374 r.colors map=current_raster -n rast=current_raster
375
377 d.colortable, d.histogram, d.legend, r.colors.out r.colors.stddev,
378 r.support, r.univar, v.colors, v.colors.out, r3.colors, r3.colors.out
379 See also wiki page Color tables (from GRASS User Wiki)
381 ColorBrewer is an online tool designed to help people select good color
383 schemes for maps and other graphics.
384
386 Michael Shapiro and David Johnson
387 Support for 3D rasters by Soeren Gebbert
388
390 Available at: r.colors source code (history)
391 Main index | Raster index | Topics index | Keywords index | Graphical
393 index | Full index
394 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
396GRASS 7.8.5 r.colors(1)