An abstract projection

abstract class Projection {
 /**
  * Project a point (lat/lon) from a geodetic coordinates into a
  * Point2D (x,y) in a projected coordinate system
  */
 Point2D project(LatLon ll);

 /**
  * Reverse project a Point2D (x,y) from a projected coordinate system into
  * a Point2D (lat/lon) in the geodetic coordinate system.
  */
 LatLon unproject(Point2D p);
}