[GRASS-user] setting no data color

GRASS GRASS user
1

I am trying to set no data, which represents ocean to blue. I see r.colors has a option to set nv to a color. I tried this and the oceans are still white. Any suggestions?

Jim

--
James (Jim) B. White
tel: (919)-380-9615
homepage: http://jimserver.net/

2

On Wed, 2008-05-21 at 18:31 -0400, jim white wrote:

I am trying to set no data, which represents ocean to blue. I see
r.colors has a option to set nv to a color. I tried this and the oceans
are still white. Any suggestions?

Jim

Jim,

.if you want to convert some of your values to NULLs then look at r.mull

.about the "nv" could you provide in detail what and how you set it? how
does your "color_settings" file look like?

3

On Thu, 2008-05-22 at 01:46 +0200, Nikos Alexandris wrote:

On Wed, 2008-05-21 at 18:31 -0400, jim white wrote:
> I am trying to set no data, which represents ocean to blue. I see
> r.colors has a option to set nv to a color. I tried this and the oceans
> are still white. Any suggestions?
>
> Jim

Jim,

.if you want to convert some of your values to NULLs then look at r.mull

Sorry,

that would be r.null

.about the "nv" could you provide in detail what and how you set it? how
does your "color_settings" file look like?

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4

Here is the color file:

0 0 0 0
1 127 96 40
2 76 153 51
3 0 99 0
4 176 48 96
5 204 165 127
6 244 244 219
7 127 127 127
8 210 44 47
9 158 248 255
nv 191 233 255
end

If I can't get it to make nulls the color I want, I can change the nulls to zeros, but prefer to keep them null.

Jim

Nikos Alexandris wrote:

On Thu, 2008-05-22 at 01:46 +0200, Nikos Alexandris wrote:
  

On Wed, 2008-05-21 at 18:31 -0400, jim white wrote:
    

I am trying to set no data, which represents ocean to blue. I see r.colors has a option to set nv to a color. I tried this and the oceans are still white. Any suggestions?

Jim
      

Jim,

.if you want to convert some of your values to NULLs then look at r.mull
    

Sorry,

that would be r.null
  

.about the "nv" could you provide in detail what and how you set it? how
does your "color_settings" file look like?

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user
    
--
James (Jim) B. White
tel: (919)-380-9615
homepage: http://jimserver.net/

5

Jim:

>>
>>> I am trying to set no data, which represents
>>> ocean to blue. I see r.colors has a option to
>>> set nv to a color. I tried this and the oceans
>>> are still white. Any suggestions?

are you sure they are really NULL? check with d.what.rast? r.univar?

Here is the color file:

0 0 0 0
1 127 96 40
2 76 153 51
3 0 99 0
4 176 48 96
5 204 165 127
6 244 244 219
7 127 127 127
8 210 44 47
9 158 248 255
nv 191 233 255
end

looks ok. It should work; was working for me yesterday.

If I can't get it to make nulls the color I want, I can
change the nulls to zeros, but prefer to keep them null.

you shouldn't have to.
have a look in the $MAPSET/colr/$MAPNAME file too if you like.

Hamish

6

jim white wrote:

Here is the color file:

0 0 0 0
1 127 96 40
2 76 153 51
3 0 99 0
4 176 48 96
5 204 165 127
6 244 244 219
7 127 127 127
8 210 44 47
9 158 248 255
nv 191 233 255
end

If I can't get it to make nulls the color I want, I can change the nulls
to zeros, but prefer to keep them null.

In what context are they showing up as white?

Is it possible that they are being treated as transparent, over a
white background? E.g. "d.rast -o ..." treats nulls as transparent, so
the null colour doesn't have any effect. If you're using gis.m, raster
layers have the equivalent option, "overlay maps from other layers
(transparent null value cells)" enabled by default. OTOH, the option
is disabled by default in the wxPython GUI.

--
Glynn Clements <glynn@gclements.plus.com>