[GRASSLIST:7165] Re: grass rasters on mapserver

Radim Blazek radim.blazek at gmail.com
Wed Jun 15 08:24:51 EDT 2005

On 6/15/05, Paolo Cavallini <cavallini at faunalia.it> wrote:
> Hi all.
> We're trying to add grass raster layers to a mapserver (UNM) application, but
> we encounter problems. Our .map definition is:
>    NAME "landsat"
>    DATA "/home/Documenti/datigrass/Toscana/PERMANENT/cellhd/sat"
> but the raster (a Landsat map) is not displayed correctly. I assume this is
> related to the mentioned 8/24 bit limitation mentioned in
> http://grass.itc.it/start.html
> However, I find contradictory notes about this:
> - in the web page I find " GRASS raster map directly read from location must
> be in 8bit", whereas in http://grass.itc.it/spearfish/README there is "Hint:
> Mapserver currently only displays 8bit/24bit Integer images."
> Is there a way to display directly grass rasters in full color, or are we
> limited to 8bit (in this case, tiff may be a better choice, but we would
> prefer to avoid data duplication).
> And where exactly is the limitation? If it is in gdal, how can qgis display
> the same rasters correctly?

GRASS raster driver in GDAL represents the color table as metadata and 
QGIS knows about that and it can use it while Mapserver cannot.
I think that the right and 'quick' solution is to ask Mapserver developers to 
add support for color tables passed in metadata. Frank plans some more advanced 
color table model but it can take years(?). The format of of metadata
was discussed
with Frank.

> All the best.
> pc
> --
> Paolo Cavallini
> cavallini at faunalia.it   www.faunalia.it   www.faunalia.com
> Piazza Garibaldi 5 - 56025 Pontedera (PI), Italy   Tel: (+39)348-3801953

More information about the grass-user mailing list