[mapserver-users] mapserver wms: srs problem

[Barend Kobben]

It looks like your datastore's SRS is 4326 (latlon on the WGS84). In other
words, the data in your shapefile, database or raster image are (or are
advertised to be) in 4326. Its because your data is indeed in that srs
and/or advertised as such in the Mapfile LAYER as

          PROJECTION
             "init=epsg:4326"
          END

But you tell the WMS interface that the layer is in 26915, by setting layer
metadata srs => EPSG:26915

If you want MS to reproject your data from 4326 to 26915 upon request, make
sure you set the layerdata projection:
        PROJECTION
             "init=epsg:4326"
          END

Then make sure you tell the WMS interface to advertise it can be reprojected
to 26915 by setting it in web metadata srs:
    "wms_srs" "EPSG:4326 EPSG:26915 EPSG:[others you want to offer]"

AFAIK there no wms_srs metadata in the LAYER object...


-- 
Barend Köbben
International Institute for Geo-Information
Sciences and Earth Observation (ITC)
PO Box 6
7500AA Enschede, The Netherlands
+31 (0)53 4874253

 



On 08-06-08 02:21, "Matthew Pettis" <matthew.pettis at gmail.com> wrote:

> Hi,
> 
> I am not a GIS guy, and am a bit confused by the projection attributes
> i have to specify in mapserver.  In particular, I have a simple
> example.  I have a map that has the following metadata:
> 
> Horizontal Coordinate Scheme     UTM
> Ellipsoid  GRS80
> Horizontal Datum  NAD83
> Horizontal Units  Meters
> UTM Zone Number  15
> 
> I believe this translates to an epsg=26915
> 
> Now, according to mapserver, I have to specify a projection object, a
> web metadata srs, and a layer metadata srs.
> 
> To compress the mapfile, i'll just note what i have specified for each
> of these settings.
> 
> First, I would think that this would work:
> 
> projection => init=epsg:26915
> web metadata srs => EPSG:26915
> layer metadata srs => EPSG:26915
> 
> this give me the error:
> msWMSLoadGetMapParams(): WMS Server Error. Invalid SRS given.  SRS
> must be valid for all requested layers.
> 
> I only have the one layer (it's of the state of MN from www.gis.leg.mn).
> 
> However, the following renders, but I don't think it is the projection
> i want (as the top of MN is too wide):
> 
> projection => init=epsg:26915
> web metadata srs => EPSG:26915
> layer metadata srs => EPSG:4326
> 
> Now, I am using mapserver as a WMS.  Before I was using it NOT as a
> WMS, but just making it render the shapefile without any projection
> information, it worked, and it was the projection I had come to expect
> when seeing the state of MN rendered.
> 
> Why does my first configuration give me an error?
> How can I make it render in the way I expect without giving mapserver
> explicit projection instructions?
> 
> please forgive the ignorance of map projection knowledge.
> 
> thanks,
> matt

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