[mapserver-users] Display GeoTIFF raster data

[Hankley, Chip]

Stefan...

In addition to Perry's comments, you can always use some of the libgeotiff
tools to help you manipulate your geotiff:

http://www.remotesensing.org/geotiff/geotiff.html

You can use the 'listgeo' program to generate an ESRI style world file, as
well as to dump the contents of the geotiff into the standard geotiff
metadata format. You can then, as Perry suggested, use your favorite Image
manipulator to convert from RGB to indexed color, then go back and use the
'geotifcp' program to convert the resulting tiff into a geotif.

The results would be the same, you just wouldn't have to worry about
maintaining a separate file. Also, if your original RGB geotiff has metadata
information in addition to that covered by the standard ESRI style world
file, it would be incorporated into your final Index-color geotiff as well.

Cheers!

Chip

-----Original Message-----
From: Pericles S. Nacionales [mailto:pnaciona at gis.umn.edu]
Sent: Monday, July 29, 2002 2:31 PM
To: 'Stefan Stern'
Cc: mapserver-users at lists.gis.umn.edu
Subject: RE: [mapserver-users] Display GeoTIFF raster data


Are you using an RGB image?  If you are, you'll need to convert it into
a bitmap (indexed color) image.  MapServer doesn't yet support RGB
images.  Hopefully, your software can export GeoTIFFs.  If not, you'll
have to create a world file (with extension .wld).  See Tom Kralidis'
info about world files: http://www.kralidis.ca/gis/worldfile.htm
Remember to use the extension ".wld" and not ".tfw".

Most image manipulation software (i.e. Gimp or Photoshop) can convert
RGB GeoTIFFs to bitmap but can't keep the GeoTIFF header.  If you use
one of these software, you'll need to create a world file to add
georeferencing to your image.  If you have an image processing software
(i.e.: Imagine, Geomatica) you can export your bitmap image in GeoTIFF
format and you won't need a world file.

Of course you should also check your projections and extents...  If
you're trying to overlay your image with the tutorial data, it won't
happen.  If you're trying to overlay a Transverse Mercator (or UTM)
projected image with unprojected (with lat/lon coordinates) vector data,
it won't happen...  unless you already know how to reproject your data
on the fly (that's section 4 on the tutorial).

I hope this helps.

-Perry

-----Original Message-----
From: owner-mapserver-users at lists.gis.umn.edu
[mailto:owner-mapserver-users at lists.gis.umn.edu] On Behalf Of Stefan
Stern
Sent: Monday, July 29, 2002 7:40 AM
To: MAPSERVER
Subject: [mapserver-users] Display GeoTIFF raster data

Hi NG,

after spending some days on trying to display a GeoTiff image in 
mapserver I ask for your advice.
Compared to the example used in the tutorial ( 
http://terrasip.gis.umn.edu/projects/tutorial35/s2/s2ex3.html ) image 
dataset is more complex.
It includes the following values for each pixel:

################
Scrn: R:146 G:103 B:50
Projection: GEOTIFF (Transverse Mercator)
Map: 267457.50E,197788.50N Meters
LL : 3.548576N, 1.228218W
Data: R:136 G:102 B:68
###############

How do I display this image in mapserver?
Do I need to rewrite header information of the source image or is it 
just a question of "How to display it in mapserver"?
Is there some additional documentation / reference available?

Thanks for suggestions.

Regards,
Stefan