[OpenLayers-Users] WMS layer with different SRS than basemap

[Guillaume Sueur]

Hi,

This is the answer I got from Chris few months ago when I asked for the
same question :
OpenLayers does not support the display of differently projected WMS
>> layers. I'm assuming that in this case, your two different projection
>> strings have the same projection, and that this isn't actually two
>> different projections like OpenLayers tries to helpfully assume it is.
>> If that's the case, then the code to modify is the getFullRequestString
>> function: specifically, doing something like this:
>>
>> OpenLayers.Layer.WMS.prototype.getFullRequestString =
>>            function(newParams, altUrl) {
>>      var projectionCode = this.projection.toString();
>>      this.params.SRS = (projectionCode == "none") ? null :
projectionCode;
>>      return OpenLayers.Layer.Grid.prototype.getFullRequestString.apply(
>>        this, arguments);
>> }

this should avoid map projection override of layer's specific projection

Hope that helps

Guillaume

Dejung Gewissler a écrit :
> Hi All-
> 
> I've searched on Nabble for the answer to this to no avail. I know you 
> all are busy with the release cycle (!kudos to all that are involved!), 
> but I was hoping someone has an easy answer for this problem.
> 
> I've got some WMS services coming from IMS or ArcGIS servers and some 
> others coming from GeoServer. Unfortunately ESRI identifies the NJ State 
> Plane (us feet) coordinate system as EPSG:102711 and GeoServer uses 
> EPSG:3432. ESRI doesn't have a EPSG:3432 and GeoServer doesn't have a 
> EPSG:102711!!! I understand that OpenLayers doesn't support raster 
> reprojection because it would be nearly impossible to do in a browser, 
> etc. My images, however, are fundamentally of the same projection, 
> albeit with a different SRS identifier. I just need them laid on top of 
> each other.
> 
> I define my map with options {... projection: 'EPSG:102711' ...} and my 
> WMS overlays with {... srs: 'EPSG:3432' ...}. The WMS overlays are 
> nonetheless being sent with SRS=EPSG:102711. It seems that OL ignores 
> the passed-in srs in the layer constructor and defaults to whatever the 
> baselayer's projection is. That makes sense in stopping the raster 
> reprojection train, but poses a problem in my situation. Is there a way 
> to force the SRS change of a WMS overlay?
> 
> Thanks,
> Dejung
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