[postgis-users] degree vs. metric projection performance?

[Picavet Vincent]

Hi,
The google mercator projection, called EPSG:900913 as <google> in
1337-speech, is now referenced as EPSG 3785 :
http://www.epsg-registry.org/report.htm?type=lastQuery&title=&reportDeta
il=short&style=urn:uuid:report-style:default-with-code&style_name=OGP%20
Default%20With%20Code&title=3785

You will find definitions in all formats here :
http://spatialreference.org/ref/user/popular-visualisation-crs-mercator/
Especially for postgis :
http://spatialreference.org/ref/user/popular-visualisation-crs-mercator/
postgis/

Bye,
Vincent

> >  By the way, are the Google Mercator and WGS84 systems equivalent
> 
> No they aren't.  I think Google is a mercator meter 
> projection (not good for measurement though but more or less 
> good for presentation) and they use WGS84 datum when 
> accepting data.  I think it actually has an official SRID 
> (could be wrong) that is EPSG:900913
> 
> and proj4 looks like this
> 
> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 
> +x_0=0.0 +y_0=0 
> +k=1.0 +units=m +nadgrids=@null +no_defs
> 
> People usually plot WGS84 longlat (4326) on Google Maps, thus 
> the confusion.
> 
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