Agustin,
Sorry for my delayed response.
The three color ramp types are, Exact, Discrete, and Interpolated.
Interpolated is the type you are looking for, I has seriously considered
changing it to linear.
If you have two entries in your color table 0 = black 10 = white.
0 ,0,0,0,255,Black
10,255,255,255,255, White
Exact will only shade pixel values 0 and 10, all other pixel values will
be ignored.
Discrete is like a bin ( 0 <= pixel < 10 shade as white) so pixel value
of 5 would he shaded as white ( 255, 255, 255, 255 )
Interpolated is basically a linear interpolation between two colors. In
this example 5 would be shaded as ( 128, 128, 128, 255 ). **note,
currently the alpha value is always 255 for the interpolated color and
should probably be marked as a bug.
-pete
Agustin Lobo wrote:
Peter,
What would be the equivalent rules for a continuous pseudocolor table
(i.e., INTERPOLATION::LINEAR ?)
Actually, do you have some standard pseudocolor tables (i.e., terrain
colors) already made?
Thanks
Agus
2009/1/14 Peter Ersts <[email protected]>:
The easies way is to make a text file (classification.txt) and add the color
entries by hand. So the contents of the file will look like:
INTERPOLATION::EXACT
11,0,0,255,255,Post-flooding or irrigated croplands (or aquatic)
14,0,255,0,255,Rainfed croplands
20,255,0,255,Mosaic cropland (50-70%) / vegetation
(grassland/shrubland/forest) (20-50%)
This will set pixels 11 to blue, 14 to green and 20 to red. The format is
really basic.
pixel value, red, green, blue, alpha, label (no commas)
Then on the colormap tab, you can click the "Load color map from file"
button, second one from the top right.
Eventually it is planned that it will be able to read a variety of different
colormap formats.
-pete
Agustin Lobo wrote:
I've got a landcover map in raster format (a tif file)
from GLOBOVER
(http://postel.mediasfrance.org/en/BIOGEOPHYSICAL-PRODUCTS/Land-Cover/)
The raster is opened in QGIS as "Single Band Grey"
How can I set an arbitrary color table? I can see how
to set a ramp, but this is a classified image, in which
integer values stand for different types
i,e,:
11 Post-flooding or irrigated croplands (or aquatic)
14 Rainfed croplands
20 Mosaic cropland (50-70%) / vegetation (grassland/shrubland/forest)
(20-50%)
for which different colors should be set as in "unique value"
for vector maps.
Thanks
Agus
--
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Peter J. Ersts, Project Specialist
American Museum of Natural History
Center for Biodiversity and Conservation
Central Park West at 79th Street
New York, New York 10024
Tel: Home Office (518)-632-4745 or NYC Office (212)-496-3488
Web: http://biodiversityinformatics.amnh.org
Web: http://cbc.amnh.org
Quantum GIS Raster Development Team. Visit http://www.qgis.org
to learn more about QGIS, a free and open source desktop GIS
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