Flags:¶

-r

Remove existing color table

-w

Only write new color table if it does not already exist

-l

List available rules then exit

-d

List available rules with description then exit
If a color rule is given, only this rule is listed

-n

Invert colors

-g

Logarithmic scaling

-a

Logarithmic-absolute scaling

-c

Convert color rules from RGB values to color table
Option ’rgb_column’ with valid RGB values required

--help

Print usage summary

--verbose

Verbose module output

--quiet

Quiet module output

--ui

Force launching GUI dialog

Parameters:¶

map=name [required]

Name of vector map
Or data source for direct OGR access

layer=string

Layer number or name
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
Default: 1

use=string [required]

Source values
Options: attr, cat, z
Default: cat
attr: read values from attribute table (requires <column> option)
cat: use category values
z: use z coordinate (3D points or centroids only)

column=name

Name of column containing numeric data
Required for use=attr

range=min,max

Manually set range (refers to ’column’ option)
Ignored when ’rules’ given

color=style

Name of color table
Options: aspect, aspectcolr, bcyr, bgyr, blues, byg, byr, celsius, corine, curvature, differences, elevation, etopo2, evi, fahrenheit, forest_cover, gdd, grass, greens, grey, grey.eq, grey.log, grey1.0, grey255, gyr, haxby, inferno, kelvin, magma, ndvi, ndwi, nlcd, oranges, plasma, population, population_dens, precipitation, precipitation_daily, precipitation_monthly, rainbow, ramp, random, reds, roygbiv, rstcurv, ryb, ryg, sepia, slope, soilmoisture, srtm, srtm_plus, terrain, viridis, water, wave
aspect: aspect oriented grey colors [range: map values]
aspectcolr: aspect oriented rainbow colors [range: 0 to 360]
bcyr: blue through cyan through yellow to red [range: map values]
bgyr: blue through green through yellow to red [range: map values]
blues: white to blue [range: map values]
byg: blue through yellow to green [range: map values]
byr: blue through yellow to red [range: map values]
celsius: blue to red for degree Celsius temperature [range: -80 to 80]
corine: EU Corine land cover colors [range: 111 to 995]
curvature: for terrain curvatures (from v.surf.rst and r.slope.aspect) [range: map values]
differences: differences oriented colors [range: map values]
elevation: maps relative ranges of raster values to elevation color ramp [range: map values]
etopo2: colors for ETOPO2 worldwide bathymetry/topography [range: -11000 to 8850]
evi: enhanced vegetative index colors [range: -1 to 1]
fahrenheit: blue to red for Fahrenheit temperature [range: -112 to 176]
forest_cover: percentage of forest cover [range: 0 to 100]
gdd: accumulated growing degree days [range: 0 to 6000]
grass: GRASS GIS green (perceptually uniform) [range: map values]
greens: white to green [range: map values]
grey: grey scale [range: map values]
grey.eq: histogram-equalized grey scale [range: map values]
grey.log: histogram logarithmic transformed grey scale [range: map values]
grey1.0: grey scale for raster values between 0.0-1.0 [range: 0 to 1]
grey255: grey scale for raster values between 0-255 [range: 0 to 255]
gyr: green through yellow to red [range: map values]
haxby: relative colors for bathymetry or topography [range: map values]
inferno: perceptually uniform sequential color table inferno [range: map values]
kelvin: blue to red for temperature in Kelvin scale [range: 193.15 to 353.15]
magma: perceptually uniform sequential color table magma [range: map values]
ndvi: Normalized Difference Vegetation Index colors [range: -1 to 1]
ndwi: Normalized Difference Water Index colors [range: -200 to 200]
nlcd: US National Land Cover Dataset colors [range: 0 to 95]
oranges: white to orange [range: map values]
plasma: perceptually uniform sequential color table plasma [range: map values]
population: color table covering human population classification breaks [range: 0 to 2e+09]
population_dens: color table covering human population density classification breaks [range: 0 to 1e+09]
precipitation: precipitation color table (0..2000mm) [range: 0 to 7000]
precipitation_daily: precipitation color table (0..1000mm) [range: 0 to 10000]
precipitation_monthly: precipitation color table (0..1000mm) [range: 0 to 1000]
rainbow: rainbow color table [range: map values]
ramp: color ramp [range: map values]
random: random color table [range: map values]
reds: white to red [range: map values]
roygbiv: [range: map values]
rstcurv: terrain curvature (from r.resamp.rst) [range: map values]
ryb: red through yellow to blue [range: map values]
ryg: red through yellow to green [range: map values]
sepia: yellowish-brown through to white [range: map values]
slope: r.slope.aspect-type slope colors for raster values 0-90 [range: 0 to 90]
soilmoisture: soilmoisture color table (0.0-1.0) [range: 0 to 1]
srtm: color palette for Shuttle Radar Topography Mission elevation [range: -11000 to 8850]
srtm_plus: color palette for Shuttle Radar Topography Mission elevation (with seafloor colors) [range: -11000 to 8850]
terrain: global elevation color table covering -11000 to +8850m [range: -11000 to 8850]
viridis: perceptually uniform sequential color table viridis [range: map values]
water: water depth [range: map values]
wave: color wave [range: map values]

raster=name

Raster map from which to copy color table

raster_3d=name

3D raster map from which to copy color table

rules=name

Path to rules file

rgb_column=name

Name of color column to populate RGB values
If not given writes color table

Define color table based on categories¶

Define color table wave based on categories from layer 1

v.colors map=soils_general layer=1 color=wave

Define color table based on attribute values¶

Define color table ryg based on values from attribute column AREA. Attribute table is linked to layer 1.

v.to.db map=soils_general layer=1 option=area column=AREA
v.colors map=soils_general layer=1 color=wave use=attr column=AREA

Define color table stored as RGB values in attribute table¶

Write color values to the attribute table (column GRASSRGB) instead of creating color table.

v.colors map=soils_general layer=1 color=wave use=attr column=AREA rgb_column=GRASSRGB
# See some GRASSRGB values:
v.db.select map=soils_general where="cat < 4"
cat|OBJECTID|AREA|PERIMETER|GSLNC250_|GSLNC250_I|GSL_NAME|GRASSRGB
1|1|0|164616.125|2|1|NC113|212:42:127
2|2|0|30785.529297|3|2|NC096|212:42:127
3|3|0|87572.882812|4|3|NC097|212:42:127

Convert RGB attribute values into color table¶

Convert existing RGB values to color table rules.

v.colors -c map=soils_general rgb_column=GRASSRGB

Note that in this case the vector map has a proper color table assigned (check by v.colors.out) together with GRASSRGB attribute column. Also note that color table is preferred over RGB values stored in attribute table.

Remove existing color table¶

Existing color table can be removed by -r flag.

v.colors -r map=soils_general

Before removing color table you can store color rules to the file by v.colors.out and later to assign by rules option.

v.colors.out map=soils_general rules=soils.colr
v.colors map=soils_general rules=soils.colr

To drop RGB column use v.db.dropcolumn.

v.db.dropcolumn map=soils_general column=GRASSRGB