libpysal.cg.
arcdist
(pt0, pt1, radius=6371.0)[source]¶Arc distance between two points on a sphere.
assumed to be in form (lng,lat)
assumed to be in form (lng,lat)
defaults to Earth’s radius
Source: http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html
Examples
>>> pt0 = (0,0)
>>> pt1 = (180,0)
>>> d = arcdist(pt0,pt1,RADIUS_EARTH_MILES)
>>> d == math.pi*RADIUS_EARTH_MILES
True