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Geographic Information Systems

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    Do you really mean calculating the distortion or do you really want to know how to calculate the projection itself? Perhaps you could make an image available on the Web to illustrate what you're trying to accomplish. Your use of "match" suggests you would like to determine how to transform one image to another, indicating you need to specify what you're starting with as well as what you want to end up with. Commented Jun 27, 2012 at 22:27
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    We understand it is hard to describe what you want to do without knowing the jargon, but it sounds like you're trying to describe the process rather than the result. Try starting with a problem you want to solve, then the results you would like, and we'll try to fill in the gaps :) Commented Jun 27, 2012 at 23:37
  • In technical terms: you want to reproject from the equirectangular projection to an orthographic ("world from space") projection. What software can you use? If you have GIS software or are willing to code against a projection library, the work is basically done for you. Otherwise, you need to implement the equations for unprojecting the equirectangular projection (easy) and projecting the orthographic projection (not too hard, but requires some skills in coding numerical routines). Commented Jun 28, 2012 at 14:07
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    I saw this post and I'm trying to basically do the exact same thing. I want to draw 2D circles that distort correctly when projected onto a 3D sphere. I was wondering if you would be willing to share the algorithm you used for the distortion of the 2D circles? Should really have been a comment not an answer, but I wrote it in the wrong spot. Sorry. Commented Jul 25, 2012 at 3:37
  • You should draw your data in 3D space then project it back to the sphere. Commented Nov 19, 2012 at 8:59