[GRASS-user] Can GRASS create color table in16 bit?

[Micha Silver]

On 1/2/21 9:13 AM, mega saputra wrote:
> Dear all,
>
> I try to create color table in 16 bit. That is in attachment. But, 
> when I set color table interactively, then I input that file (in 
> attachment), then I click Load. There is a message : "Invalid color 
> table format". Do I missing something?
>

I think you have the categories and colors backwards. RGB color tables 
are (throughout all GIS and image software) always three 8 bit numbers, 
with optionally a fourth alpha band, also 8 bit. In your rules file you 
attach raster values (16 bit numbers in your case) to certain RGB 
values.  So, To define a color table for your raster you put the raster 
values in the left column and R:G:B (0-255) combinations in the right 
column.


Here's an example of the srtm (elevation) builtin color table. Maybe you 
can use it as a template.


-11000 0:0:0
-500 0:0:10
-300 0:0:20
-200 0:0:70
-100 0:0:130
-50 0:0:205
0 100:128:255
0.1 57:151:105
100 117:194:93
200 230:230:128
500 202:158:75
1000 214:187:98
2000 185:154:100
3000 220:220:220
5000 250:250:250
8850 255:255:255
nv 255:255:255
default 255:255:255


It spans the range of elevations from sea bottom (-11000 m) to the peak 
of the Himalaya Mts. (8850 m)


HTH


> Thank you.
>
> Regards,
> mega
>
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-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918