[OpenLayers-Dev] wms layer on sphericalmercator

[Christopher Schmidt]

On Mon, Sep 22, 2008 at 11:07:22AM +0200, Jachym Cepicky wrote:
> hi,
> 
> previously, it was possible, to overlay e.g. WMS layer on top of
> SphericalMercator layer (google), as demostranted in example [1].
> According to documentation [2], using reproject:true is deprecated now.
> 
> According to available documentation [3][4], it is no longer possible
> to overlay e.g. WMS Layer in epsg:4326 on top of google maps layer.
> You have two possibilities now:
> 
> 1) setup your wms server, so it supports epsg:900913 on the output
> 2) create proxy wms, which will accept epsg:4326 on the input and
> covert the images to epsg:900913 on the output
> 
> Do I miss some point? Could the deprecated "reproject" attribute go
> back to OpenLayers, so you could overlay epsg:4326 on top of
> epsgf:900913?

Speaking for myself: No. It creates too many problems:
 * People don't understand that it is by neccessity inaccurate; 
   browsers can't actually reproject, so the stretching doesn't end up
   correct.
 * The support didn't work with some WMS servers anyway, because it
   requires support for non-square pixels, which isn't universal.

It will stick around until the 3.x series, by which tie the
understanding of the 'web mercator' projection should be sufficiently
widespread to make the requirement of 1) less ardurous, but I am
strongly against keeping the reprojection option around after that.

Regards,
-- 
Christopher Schmidt
MetaCarta