WMS Raster Layer service

[Frank Warmerdam]

On Fri, 14 Jan 2005 03:04:09 -0000, Ganesh P <ganny_3 at rediffmail.com> wrote:
>
>
>  Hello Everyone
>
>  First of all, Thank you very much Steve and Brent for your immediate
> responses. I apologize for the late reply as i was away for a couple of
> days.
>
>  Now, i get the point that all the raster layers can be indexed together
> using GDALTINDEX and using TILEINDEX in the Map file layer. I did the
> GDALTINDEX on all our raster layers using :
>
>  gdaltindex sample.shp /usr/images/*.tif
>
>  It didnot give any errors and created a shape file. I checked the dbf file,
> and it contains a list of all the raster files. I added a new layer to my
> map file using the following :
>
>  Layer
>        Name "Mosaic"
>        Type Raster
>        status default
>        Tileindex "/var/www/map/sample.shp"
>        Tileitem "Location"
>  End
>
>  But, when i enable the layer, it gives me a blank image. I think Mapserver
> is ignoring this layer. Not sure if i am making a mistake in the layer
> definition or GDALTINDEX input (with raster images).
>
>  Regarding the raster images we have, some cover same area and some cover
> different area with overlaps, and different acquisition dates. Some images
> have 1 band, some have 3 and some have 7 bands. Also, the images have
> different projections (UTM 13, 14, 15, 16, ....) and are obtained from
> different sensors.
>
>  As a whole the images have different coverages, dates, number of bands and
> projections. I have a doubt if this is causing the problem. If this is the
> case, then please suggest me how do i classify my raster images, is it done
> based on their projection or coverage or number of bands (to run separately
> on GDALTINDEX)?
>  After grouping the raster images based on some criteria, i have to run
> GDALTINDEX on each group and add different layers in the map file, is that
> Correct ?

Ganesh,

You will definately need a seperate layer and tile index
for each projection for which you have raster files.  MapServer
uses the projection declaration on the layer to interprete
the coordinates from the file, ignoring the coordinate system
actually stored in the file.

However, it is OK to mix different types of files in one
tile index.  For instance, different number of bands, dates,
etc.  Each image that overlays the map area will be rendered
in turn according to it's configuration and the layer information.

I suspect your main problem is the coordinate systems.  Is
your map in UTM coordinates?  Which zone?  If not, you
will need to declare the projection for the map as a whole,
and the projection for any raster layers.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent