libpysal.cg.fast_knn¶

libpysal.cg.fast_knn(pts, k, return_dist=False, radius=6371.0)[source]¶

Computes \(k\) nearest neighbors on a sphere.

Parameters:¶

pts : list¶

A list of \(x,y\) pairs.

k : int¶

The number of points to query.

return_dist : bool¶

Return distances in the wd container object (True). Default is False.

radius : float¶

The radius of a sphere. Default is Earth’s radius in kilometers, RADIUS_EARTH_KM (6371.0). Earth’s radius in miles, RADIUS_EARTH_MILES (3958.76) is also an option. Source: http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html

Returns:¶

• wn (dict) – A neighbor ID lookup.

• wd (dict) – A neighbor distance lookup (optional).