distlatlon

distlatlon(lat1, lon1, lat2, lon2 [, method] )

The distlatlon function calculates the distance, in miles, between two points, represented in latitude/longitude pairs in decimal degree format.

Like distgeocode, it uses the "Great Circle" method by default, but can be overridden to use the faster, less accurate Pythagorean method if "pythagorean" is passed as the optional method parameter.

For example:

New York (JFK) to Cleveland (CLE), the Pythagorean method is off by .8 miles (.1%)
New York (JFK) to Los Angeles (LAX), the Pythagorean method is off by 22.2 miles (.8%)
New York (JFK) to South Africa (PLZ), the Pythagorean method is off by 430 miles (5.2%)