double getDistance(string x1, string y1, string x2, string y2)

This method calculates the geodetic distance, i.e. the distance along a great circle, between two points, given by (x1, y1) and (x2, y2), where the given coordinates are assumed to be referred to the Exchange Coordinate System, unless the map is of type NRMR (See Map Types).  In the latter case, the given coordinates are assumed to be in the map's own coordinate system and the linear distance between the points is calculated.

For NRMR maps that represent vertical profiles, this method expects incoming y-values to be non-scaled. This is most appropriate, because all methods that return coordinates return y-values that are non-scaled.  Therefore, such values can be input to this method directly. 

The returned value is in meters.