A couple of weeks ago I notified strange raster layer behaviour and I would now like to share with you how we solved the problem:
We observed a slight shift when the raster layer was displayed in OpenLayers. The shift seemed to be dependent on scale and GetFeatureInfo requests were not affected. That means that, although the pixel class was not the expected one, the returned value was always correct. We did not observe this behaviour in the thick client we use to check our map services and therefore concluded that the underlying WMS was correct and that the shift had something to do with how OpenLayers displays raster layers. And the end it turned out that the test client did not display the layer correctly either – we just happened to look at a scale where the shift was very small. So, OpenLayers was off the hook and we went back to MapServer. We finally changed the configuration to allow non-square pixels - the raster layer pixels are defined in decimal degrees and thus are irregular. For those who have been working for years with MapServer and didn’t even know that this parameter existed, this did the trick: CONFIG MS_NONSQUARE yes According to the manual, this should be the default, but it seems that MapServer doesn’t always ‘remember’ this. Now everything is back in place. Thanks, Bart, for the hint. Kind regards, Stefanie _______________________________________________ Users mailing list Users@openlayers.org http://openlayers.org/mailman/listinfo/users