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Diffstat (limited to 'docs/source')
| -rw-r--r-- | docs/source/geodesic.rst | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/docs/source/geodesic.rst b/docs/source/geodesic.rst index 0f31802d..fac3649c 100644 --- a/docs/source/geodesic.rst +++ b/docs/source/geodesic.rst @@ -66,16 +66,18 @@ the earth. This from Mikael Rittri on the Proj mailing list: For the fixed Earth radius, I would choose the average of the: - c = radius of curvature at the poles, - b^2^ / a = radius of curvature in a meridian plane at the equator, + :math:`c` = radius of curvature at the poles, + + :math:`\frac{b^2}{a}` = radius of curvature in a meridian plane at the equator, since these are the extreme values for the local radius of curvature of the earth ellipsoid. If your coordinates are given in WGS84, then - c = 6 399 593.626 m, - b^2^ / a = 6 335 439.327 m, + :math:`c` = 6 399 593.626 m, + + :math:`\frac{b^2}{a}` = 6 335 439.327 m, (see http://home.online.no/~sigurdhu/WGS84_Eng.html) so their average is 6,367,516.477 m. The maximal error for distance calculation should then be less than 0.51 percent. |