[Proj] Google maps of various flavors, and countries all over the place.

[Hamish]

Roger Oberholtzer wrote:
> I have been asked by a colleague about the possibility of providing  
> our data using coordinates that can be displayed over a google map. I  
> recall a short discussion about this a while back, but do not recall  
> if any potential method was discovered. I see on the proj4 trac site  
> that there is a reference in the context of a guess about google maps.
> 
> BTW, our data starts life as WGS85 from a Trimble receiver.
> So that  would be our starting point.

my understanding is that google uses mercator-on-sphere for their maps,
but user supplied point coords to their software should be in WGS84
lat/lon.

http://trac.osgeo.org/proj/wiki/FAQ#ChangingEllipsoidWhycantIconvertfromWGS84toVirtualEarthMercator


$ tail -n 4  /usr/share/proj/esri.extra 
#
#  Chris' funny epsgish code for the google mercator
#
<900913> +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 +wktext  +no_defs <>



Hamish