[Mapserver-users] RE: Using Mapserver & GDAL to find elevation

[Matt Doggett]

What I do in my PHP/mapscript is call an external program to query the
raster cell values. In my case, the rasters are GRASS grids so all I
have to do is setup my GRASS environment and then call the 'system'
function (eg.  System "r.what ...") and return the results back to the
query window. No matter what you go with, it looks like having a 3rd
party piece of software is mandatory.

Matt

>-----Original Message-----
>From: mapserver-users-admin at lists.gis.umn.edu [mailto:mapserver-users-
>admin at lists.gis.umn.edu] On Behalf Of Arthur, John
>Sent: Wednesday, February 11, 2004 12:29 PM
>To: 'Frank Warmerdam'
>Cc: mapserver-users at lists.gis.umn.edu
>Subject: [Mapserver-users] RE: Using Mapserver & GDAL to find elevation
>
>Thanks Frank.  Is there any other ideas outside of mapserver, maybe?
>
>-----Original Message-----
>From: Frank Warmerdam [mailto:warmerdam at pobox.com]
>Sent: Wednesday, February 11, 2004 3:19 PM
>To: Arthur, John
>Cc: mapserver-users at lists.gis.umn.edu
>Subject: Re: Using Mapserver & GDAL to find elevation
>
>
>Arthur, John wrote:
>> Hello all,
>>
>> 	I have a project where I need to be able to find the ground
elevation
> >of coordinates on the fly.  The file format we have is supposedly a
>proprietary
> >format, but I believe it is close to the "ArcInfo Binary Grid".  How
>would I go
> >about finding the elevation using mapscript (or some other way)?
Will
>mapserver
> >even read this format (by way of GDAL/OGR)?
>
>John,
>
>GDAL will read Arc/Info Binary Grids, so if it is sufficient close to
this,
>it may work.
>
>However, currently MapServer and MapScript do not provide a way to
query
>raster values.  The only thing you can do with rasters is render them
in a
>mapview.
>
>There is an intent to get query operations (in the usual mapserver
sense)
>working for rasters as well as vectors.  At that point there might be
some
>mechanism provided for reading query results back from within
MapScript.
>But that isn't going to be immediate.
>
>Best regards,
>
>--
>---------------------------------------+-------------------------------
----
>---
>I set the clouds in motion - turn up   | Frank Warmerdam,
>warmerdam at pobox.com
>light and sound - activate the windows | http://pobox.com/~warmerdam
>and watch the world go round - Rush    | Geospatial Programmer for Rent
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