[Proj] proj4 string for perfect sphere

support.mn at elisanet.fi support.mn at elisanet.fi
Tue Apr 17 04:54:11 EST 2012


Demitri Muna [thatsanicehatyouhave at me.com] kirjoitti: 
> Hi Bob,
> Thanks very much for the extensive comments. The biggest thing I learned about GIS this week (starting from knowing nothing about it last week) is that calculations are primarily done on an XY plane which are projections of a curved surface. I had naively assumed going in that calculations and indices (e.g. spatialite) were optimized for the surface of a sphere.

A small notice for a beginner: If you want to stay accurate and avoid lots of trouble with projections generated errors never leave the sphere (or ellipsoid) just keep doing all calculations there - it is much easier (you don't need projections) and you will stay accurate for ever ;)

regards: Janne.

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