[Gdal-dev] Projected vs Geographic Coordinate Systems

Joaquim Luis jluis at ualg.pt
Tue Mar 20 14:28:08 EDT 2007

Simon Perkins wrote:
> I think that google maps does everything in Mercator, but google earth
> allows you to view the entire globe, spin it around and view the poles,
> so my feeling is it must be doing something more cunning.
Google Earth could also have been named "Google Land" because only
over continents (but except Antarctica) we have satellite imagery draped
on DEMs (of variable resolution). The ocean areas are represented by an
image constructed from the Smith & Sandwell predicted bethymetry grid.
That is why you see those kind of tiles over the north pole.

Note that it is also possible to have it display the pointer coordinates 
in UTM.

Joaquim Luis

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