[OpenLayers-Users] EPSG:900913 or SR-ORG:6 or EPSG:3785?

[christopher.schmidt at nokia.com]

On Feb 12, 2011, at 1:59 PM, ext Stefan Keller wrote:

> Hi,
> 
> I'm confused about the 'right' coordinate reference system while
> having to decide with which srid to take on a geometry (PostGIS).
> 
> When looking at
> http://dev.openlayers.org/releases/OpenLayers-2.10/doc/apidocs/files/OpenLayers/Layer/SphericalMercator-js.html
> it says "Transforms from EPSG:4326 to EPSG:900913 and from EPSG:900913
> to EPSG:4326 are set by this class."
> 
> * When looking up EPSG:900913 on spatialreference.org it finds nothing.
> * There's a link in the doc. to
> http://spatialreference.org/ref/sr-org/google-projection/ which
> actually indicates SR-ORG:6 (I expected EPSG:900913)
> * I read about another EPSG:3785
> (http://spatialreference.org/ref/epsg/3785/) which says "Popular
> Visualisation CRS / Mercator"
> 
> 1. Is EPSG:900913 really the one used by Google Maps API and is it up-to-date?
> 2. Should someone update spatialreference.org with EPSG:900913 (or is
> this a synonym of/equivalent to EPSG:3785 and SR-ORG:6)?
> 3. As of now, the doc. shoud explain why
> http://spatialreference.org/ref/sr-org/google-projection/ whows
> SR-ORG:6 and not EPSG:900913!

EPSG is an official, trademarked name. Putting things into the EPSG namespace --
like we (OpenLayers developers) have done with EPSG:90013 -- does not make them
happy. Although OpenLayers is happy to use EPSG:900913, Spatial Reference .org
attempts to act as an official repository in the EPSG: namespace, so we do not add
'fake' entries to that dataset.

EPSG:3785 was the 'old' EPSG code for what we call EPSG:900913.

This was replaced by EPSG:3857, which is the 'new' EPSG code for what we call 
EPSG:900913.

The proj4/WKT from SR-ORG:6 is the right proj4 for EPSG:900913 as we use it
in OpenLayers.

It seems that all of your problems are with sr.org, not with OpenLayers,
so I recommend you take your concerns to the MetaCRS list. If you feel 
strongly about the OpenLayers doc issue, feel free to submit a patch.

-- Chris

> Yours, S.
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