great_circle_distance

typhon.geodesy.great_circle_distance(lat1, lon1, lat2, lon2, r=None)

Calculate the distance between two geographical positions

This is the ‘As-the-crow-flies’ distance between two points, specified by their latitude and longitude. This uses the so-called haversine formula, defined by:

$$d=2\arcsin \left(\sqrt{\sin {\left(\frac{{\phi }_2-{\phi }_1}{2}\right)}^2+\cos ({\phi }_1)\cdot \cos ({\phi }_1)\cdot \sin {\left(\frac{{\lambda }_2-{\lambda }_1}{2}\right)}^2}\right)$$

Parameters:

• lat1 – Latitude of position 1.

• lon1 – Longitude of position 1.

• lat2 – Latitude of position 2.

• lon2 – Longitude of position 2.

• r (float) – The radius (common for both points).

Returns:

If the optional argument r is given, the distance in m is returned. Otherwise the angular distance in degrees is returned.