WMS Raster Layer service

[Stephen Woodbridge]

Typically, most mapfiles serving images use a tileindex so that the
images are automatically seamed together. if you have more than one set
of rasters like a color set, a mono set, or other dated sets, then each
set is put in a separate tileindex and is a separate layer, then you can
just turn on the layer and it will show correcly. You don't have to use
mapscript to change the data source.

If you do this, then the wms works the same way and you never need to
edit the data source for the layer, it just works. Also you don't need
to maintain a database either.

You might already know this, and have implemented your scheme for other
reasons, but it just seems like what you are trying to do is already
implemented in mapserver and is simpler to do than reimplementing wms
requests on top of mapserver that already supports this.

My good friend, Ed at Topozone has over 250,000 geotiff that he is
serving with mapserver in this way. :)

-Steve

Ganesh P wrote:
> Hello everyone,
>
> We have been successfully using Mapserver(PHP/Mapscript) for WMS client
> and Server and everything is working fine. Thanks to all the MapServer
> Developers and Users. Currently, we are using WMS server to deliver
> vector layers as PNG images. Now, we are planning to extend the server
> functionality by delivering Raster layers(GeoTiff) as PNG images.
> Currently, in our system we have around 600 geotiff images. In our
> standalone system, We search the database everytime with the current map
> extent and display a list of images covering the current extent. When
> the user selects an image, that image will be displayed on the map
> window. This is how we implemented our system. The map file contains a
> raster layer with DATA field set dynamically (using PHP/Mapscript) with
> the image name. We would like to do the same for WMS server, that is,
> when the client requests a raster layer using a bounding box in the URL,
> the most recent image which covers the requested bounding box should be
> searched in the database and returned to the client as PNG.
>
> My concerns are:
>
> 1. How do we set the raster layer in map file for WMS server and
> dynamically fill in the DATA field with the exact image name (out of 600
> images) covering the bounding box?
>
> 2. Can we use Mapserver to do this, or do we have to write a custom
> program to read the WMS client's URL, manually search the database, Cut
> the image for the requested bounding box, convert the image into PNG and
> send it to the client ?
>
> Any suggestions or information is greatly appreciated.
> Thank You very much in advance.
>
> Regards
>
> Ganesh Pulicherla
> Digital-NGP Developer
> Upper Midwest Aerospace Consortium
> University of North Dakota
>
>
>
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