using Mapserver for on-the-fly raster data?

[Sean Gillies]

On Jul 6, 2005, at 9:32 AM, Jeff de La Beaujardiere wrote:

> I have a set of huge raw binary datafiles containing output from
> someone's numerical simulation (6GB/file, 4files/day). Each file
> contains values for a variety of atmospheric quantities, each at 20
> timesteps, and some at multiple elevations. I would like to offer
> access to at least some of the quantities via WMS protocol using
> Mapserver.
>
> The brute force way works: I can pre-generate PNG or GeoTIFF images of
> selected quantities, and then generate a mapfile that includes all the
> images. The obvious disadvantage is that I will have many files laying
> around whether they ever get used or not.
>
> I would like a more elegant approach, wherein Mapserver's WMS service
> metadata can advertise what quantities are available, but the data are
> extracted from the 6GB model file only upon request. Is it possible to
> do something like this? I see a few mentions of database connections
> in the Mapserver documentation but must admit that I am somewhat
> mystified.
>
> Thanks for any help,
> Jeff DLB
>
>

Jeff,

You could take advantage of MapServer's cascading WMS, and of 
MapServer's easy-going WMS client nature. Create a custom service (as a 
CGI or servlet or whatever) that responds to WMS GetMap requests and 
generates a response on-the-fly from your model output. Next, stand up 
a MapServer WMS between this half-baked service and your end users. All 
the capabilities metadata would be defined in this mediating service. 
As a WMS client, MapServer doesn't care whether the service it requests 
from implements all the WMS spec, it only needs GetMap.

cheers,
Sean

--
Sean Gillies
sgillies at frii dot com
http://zcologia.com