[AstroPy] General method to compute pixel solid angle for any WCS projection?

Christoph Deil Christoph.Deil at mpi-hd.mpg.de
Thu Dec 5 09:07:10 EST 2013


Hi,

does anyone know a good general method to compute pixel solid angles for arbitrary WCS FITS maps?

I know there is HEALPIX and for some WCS projections there are analytical formulae for pixel area, but I was wondering if there is a standard robust method to implement it for any WCS.

I did find methods to compute the area of polygons on the sphere:
http://stackoverflow.com/questions/4681737/how-to-calculate-the-area-of-a-polygon-on-the-earths-surface-using-python
Would representing each pixel as a 4-corner polygon (or subdividing the pixel sides into parts if the pixels are large and precision is needed) and using that method be the best option?

Christoph


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