[Proj] Changing Radius of the Earth?
Fischer, Robert P. (GISS-6110)[COLUMBIA UNIVERSITY]
robert.p.fischer-1 at nasa.gov
Tue Apr 10 10:16:38 EST 2012
How do I change the radius of the (spherical) Earth in proj.4? I'm using the proj.4 string:
" +proj=laea +lon_0=-40.000000 +lat_0=74.000000 +x_0=1000000 +y_0=1700000 +ellps=sphere"
..and have discovered that proj.4 assumes a radius of exactly 6370997m (from pj_ellps.c):
"sphere", "a=6370997.0", "b=6370997.0", "Normal Sphere (r=6370997)",
We are running code on a spherical Earth, with a radius (slightly) different from that above. For consistency sake, proj.4 will need to use the same Earth radius as the code that calls it. How do I set up a projection on a spherical Earth with a custom radius?
Also... if someone wanted to use proj.4 for mapping on Mars, how would they do that?
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