question: public boolean isOnMap ( Projection proj ) { Point2D p1 = proj . forward ( lat , lon ) ; Point2D p2 = proj . forward ( lat2 , lon2 ) ; int h = ( int ) Math . abs ( p2 . getY ( ) - p1 . getY ( ) ) ; int w = ( int ) Math . abs ( p2 . getX ( ) - p1 . getX ( ) ) ; Rectangle imageRect = new Rectangle ( ( int ) p1 . getX ( ) , ( int ) p1 . getY ( ) , w , h ) ; proj . forward ( proj . getUpperLeft ( ) , p1 ) ; proj . forward ( proj . getLowerRight ( ) , p2 ) ; h = ( int ) Math . abs ( p2 . getY ( ) - p1 . getY ( ) ) ; w = ( int ) Math . abs ( p2 . getX ( ) - p1 . getX ( ) ) ; Rectangle mapRect = new Rectangle ( ( int ) p1 . getX ( ) , ( int ) p1 . getY ( ) , w , h ) ; return mapRect . intersects ( imageRect ) ; }
target:  Test to see if projected image is on map.