# Patch number to do radians conversion
Number.prototype.toRad= ->
	return this * Math.PI / 180;

#takes lat/lng in format 50.000 / 0.5400, returns distance in KM
geodistance= (lat1,lon1,lat2,lon2)->
	R = 6371; # Earth Radius
	dLat = (lat2-lat1).toRad()
	dLon = (lon2-lon1).toRad()
	lat1 = lat1.toRad()
	lat2 = lat2.toRad()

	a = Math.sin(dLat/2) * Math.sin(dLat/2) +
	        Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2);
	c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
	R * c