[Mapserver-users] rasters with more then 256 colors with gdal

[Matt Doggett]

I've had this happen before.  In my case it was the processing directive
actually worked but the reclassified values in the DEM were all on the
"small" end of the spectrum, since I didn't have any color
classifications defined, they rendered black, or very nearly black.  The
default colorscale is a black-white (greyshade) where black is zero (or
in the case of processing directive the smallest number) and white is
255 (or the largest). 

I actually gave up trying to get the processing directive to work and
used grass to reclassify my rasters into something less than 256
categories. Mapserver has no problems rendering those rasters.  It sure
would be nice to know if they had plans to fix it so that it will work
with rasters >256 cats....what a pain! :{

HTH.
md

-----Original Message-----
From: mapserver-users-admin at lists.gis.umn.edu
[mailto:mapserver-users-admin at lists.gis.umn.edu] On Behalf Of Ed
McNierney
Sent: Thursday, June 12, 2003 5:16 AM
To: Stephan Holl
Cc: mapserver-users
Subject: RE: [Mapserver-users] rasters with more then 256 colors with
gdal

Stephan -

Those look like two very different maps.  They don't appear to be the
same location, and one of them is a point elevation image (DEM) and the
other is a labeled vector contour map (I think).

I'm not a GRASS user at all, but I would first eliminate the vector
overlay and try to get the DEM working first by itself.  Can you confirm
(using a different visualization tool) that the DEM image is loaded
correctly into GRASS?  It obviously won't come OUT right if it didn't go
IN right.

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: (978) 251-4242  Fax: (978) 251-1396
ed at topozone.com


-----Original Message-----
From: Stephan Holl [mailto:sholl at gmx.net] 
Sent: Thursday, June 12, 2003 4:09 AM
To: Ed McNierney
Cc: mapserver-users
Subject: Re: [Mapserver-users] rasters with more then 256 colors with
gdal

At Wed, 11 Jun 2003 12:21:53 -0400 Ed McNierney wrote:

Hello Ed,

> Can you give us a description (with pictures, if possible) of the
> result you're trying to produce?  It's hard to tell what "comparable
> to a geotiff" means, since a geotiff can look like anything at all. 
Of course I can send you some pics.
There is a dem-raster-file, which is read as geotiff and renders nicly
through mapserver.
http://www.8ung.at/stephan.holl/tmp/dem_from_tiff.png

but when I try to access the dem from a GRASS-database through gdal it
renders all black as seen here (some contours are above...)
http://www.8ung.at/stephan.holl/tmp/dem_from_grass_through_gdal.png

As I read on the list, there should be the processing-directive to
auto-scale the image.
But when I do 
LAYER 
  [...]
  PROCESSING "SCALE=AUTO"
  [...]
END
nothing happens.

I also tried to set in the lowest and the higest point o the dem
PROCESSING "SCALE=1089, 2332"
but same result as above.

What am I doing wrong ?!
-- 
Stephan Holl

GnuPG Key-ID: 11946A09 

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