Jeff Whitaker wrote:
Dr. Phillip M. Feldman wrote:
Jeff Whitaker wrote:
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Philip: That's an error from the proj4 c library saying that it didn't like one of the parameters you used to define the projection. Since you didn't include the parameters you used, I can't say which one is the culprit.-Jeff
Philip: I believe that lat_0 must be zero for the geostationary projection (you have to be looking down on the equator). I usually leave the lat_0 parameter off entirely, in which case zero is assumed. I'll try to catch that and raise a more insightful error message.
-Jeff
Hm. I suppose that you are right. "Geostationary" does imply that the viewer is 35786.2 km above the equator.
What would be more useful is a geosynchronous projection. This would allow the viewer to be located at any latitude. Geostationary is a special case of geosynchronous.
Even more useful than a geosynchronous projection is a camera projection that allows one to place the viewer at any location in space (i.e., any latitude and longitude for the nadir point, and any altitude). (I wrote something like this is Fortran 25 years ago). Generalizing the existing geostationary projection to turn it into a camera projection would make it far more useful. I hope that someone will consider making this change.
Phillip