Do you need ellipsoidal earth for orthographic, or is spherical sufficient?
Philip Bentley wrote: > Hi Don, > > Vertical Perspective projection made it into CF 1.2, which is why I > didn't mention it. Yes, I was also assuming that GoogleEarth uses a > tilted perspective-type projection. But for general whole-globe views, > the orthographic projection is a useful alternative (and obviously the > limiting case of vertical perspective - i.e. the perspective point is at > inifinity). > > Regards, > Phil > > On Wed, 2008-05-21 at 07:05 -0400, Don Murray wrote: >> Phil/Ethan- >> >> Philip Bentley wrote: >> >> > An obvious one perhaps, but one which we may find increasingly useful / >> > relevant in light of the rise and rise of GoogleEarth-type applications, >> > is the Orthographic projection. This being the classic 'view from space' >> > projection. >> > >> > Same grid mapping parameters as the other azimuthal projections, viz. >> > >> > grid_mapping_name = "orthographic" >> > >> > longitude_of_projection_origin >> > latitude_of_projection_origin >> > false_easting >> > false_northing >> > >> > (though off the top of my head I can't think of a scenario where one >> > would want to use the last two params). >> >> I think GE actually uses a tilted perspective view. But, >> I think CF should support the Vertical Perspective with >> an ellipsoid. EUMETSAT has GRIB messages with this projection >> and an elliptical earth. >> >> Don > > ------------------------------------------------------------------------ > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
