libpysal.cg.arcdist2linear

libpysal.cg.arcdist2linear(arc_dist, radius=6371.0)

Convert an arc distance (spherical earth) to a linear distance (R3) in the unit sphere.

Examples

>>> pt0 = (0,0)
>>> pt1 = (180,0)
>>> d = arcdist(pt0,pt1,RADIUS_EARTH_MILES)
>>> d == math.pi*RADIUS_EARTH_MILES
True
>>> arcdist2linear(d,RADIUS_EARTH_MILES)
2.0