[OpenLayers-Dev] WMS request mod

Ray Di Ciaccio ray.diciaccio at ll.mit.edu
Thu May 19 12:00:22 EDT 2011

Sorry for the previous messed up message. Let me try this again:

Hi all,

I'm in what I'm guessing is a fairly common situation -- I'm using 
Google Maps as my baselayer (so map is in EPSG:9009l3 projection) and 
I'm trying to load an overlay from a WMS which I have no control over. 
It only offers data in EPSG:4326. The WMS request generated by 
OpenLayers will be for CRS=EPSG:900913 and the BBOX values will be in 
EPSG:900913. This obviously won't work if the WMS only offers EPSG:4326. 
My solution to this problem was to override 
OpenLayers.Layer.WMS.getFullRequestString() so that it uses the 
projection that I set for that particular layer -- it changes the 
CRS/SRS param to whatever the layer projection is, and it transforms the 
BBOX values from the map projection to the layer's projection. This way 
I get a valid request for the WMS and it's loaded in the correct 
location on the basemap. My question is whether this is the right 
approach to this situation and whether there may be unforeseen 
repercussions to these changes I made.

- Ray

Ray Di Ciaccio
MIT LL, Group 42
ray.diciaccio at ll.mit.edu

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