The Haversine formula will get you most of the way there. It provides the distance between two pairs of lat/long and takes into account the curvature of the earth.
Depending on the distances involved (e.g. 6km) then the curvature of the earth isn't going to make much a difference from relatively simple trig.
The Haversine formula will get you most of the way there. It provides the distance between two pairs of lat/long and takes into account the curvature of the earth.
Depending on the distances involved (e.g. 6km) then the curvature of the earth isn't going to make much a difference from relatively simple trig.