GeodeticCalculator

The GeodeticCalculator is used to perform calculations on the Geoid (i.e. on the surface of the world).

You can configure your GeodeticCalculator to work with a specific Ellipsoid (or commonly from an CoordinateReferenceSystem) and then use it to perform a number

References:

• http://udig.github.io/docs/dev/tool_plugin_tutorial.html

Distance

• Distance between two points

          // the following code is based on JTS.orthodromicDistance( start, end, crs )
          GeodeticCalculator gc = new GeodeticCalculator(crs);
          gc.setStartingPosition(JTS.toDirectPosition(start, crs));
          gc.setDestinationPosition(JTS.toDirectPosition(end, crs));
  
          double distance = gc.getOrthodromicDistance();
  
          int totalmeters = (int) distance;
          int km = totalmeters / 1000;
          int meters = totalmeters - (km * 1000);
          float remaining_cm = (float) (distance - totalmeters) * 10000;
          remaining_cm = Math.round(remaining_cm);
          float cm = remaining_cm / 100;
  
          System.out.println("Distance = " + km + "km " + meters + "m " + cm + "cm");
  

  Although the above shows quickly creating a Position from a JTS Coordinate; you can use the GeodedicCalculator with any two positions, internally it will transform the points as needed.

• You can also generate the angle between the two points

  Continuing on from the previous example:

          double angle = gc.getAzimuth();
  
          System.out.println("Angle = " + angle);
  

• Generate location away from a point

  Finally you can turn the tables and use the GeodeticCalculator to generate a point a set direction and distance away from your starting point.

          GeodeticCalculator calc = new GeodeticCalculator();
          // mind, this is lon/lat
          calc.setStartingGeographicPoint(45.4644, 9.1908);
          calc.setDirection(90 /* azimuth */, 200 /* distance */);
          Point2D dest = calc.getDestinationGeographicPoint();
          System.out.println("Longitude: " + dest.getX() + " Latitude: " + dest.getY());