public Viewport getViewport() {
            if (viewport == null && valid) {
                viewport = new Viewport(new Geopoint(latMin, lonMin), new Geopoint(latMax, lonMax));
            }
            return viewport;
        }
Helper class to build Viewports without instanciating too many helper objects
main/src/main/java/cgeo/geocaching/location/Viewport.java