Display Geotiff-Data: Problems

[Frank Warmerdam]

On 5/23/05, Wolfgang Qual <Wolfgang.Qual at muenchen.de> wrote:
> Hello List,
> I have created a mapserver map with a small Geotiff in it and the map
> can be openend, when I click on the
> link(http://dream.lrrl.arch.tu-muenchen.de/cgi-bin/M3.cgi?map=geotiff2.dfo.map).
> However, the image is not displayed correctly: it is quite grainy and
> the colours are odd (compared to the picture I get on my local computer
> with kuickshow). Does anybody know the answer to this problem? Thanks again!

Wolfgang, 

You are suffering from classic color reduction to 8bit degredation. 
The normal fix is to switch to returning JPEG instead of gif/png8 images. 
Other options include turning on dithering, or returning PNG24.

This is covered in this FAQ:
  http://ms.gis.umn.edu/docs/faq/EightBitColorCompression

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent