- int off_x;
- int off_y;
-
- static final int px_size = 512;
-
- private void loadMap() {
- Point2D.Double map_latlng = latlng(px_size/2, px_size/2);
- mapLabel.loadMap(map_latlng.x, map_latlng.y, zoom, px_size);
- }
-
- private boolean setLocation(double lat, double lng) {
- Point2D.Double north_step;
- double step_nm = 0.5;
- for (zoom = 3; zoom < 22; zoom++) {
- coord_pt = pt(lat, lng, new Point2D.Double(0,0), zoom);
- north_step = pt(lat+step_nm/60.0, lng,
- new Point2D.Double(0,0), zoom);
- if (coord_pt.y - north_step.y > px_size/2)
- break;
- }
- coord_pt.x = -px_size * Math.floor(coord_pt.x/px_size + off_x);
- coord_pt.y = -px_size * Math.floor(coord_pt.y/px_size + off_y);
-
- scale_x = 256/360.0 * Math.pow(2, zoom);
- scale_y = 256/(2.0*Math.PI) * Math.pow(2, zoom);
-
- last_pt = null;
-
- return true;
- }
-
- private static double limit(double v, double lo, double hi) {
- if (v < lo)
- return lo;
- if (hi < v)
- return hi;
- return v;
- }
-
- // based on google js
- // http://maps.gstatic.com/intl/en_us/mapfiles/api-3/2/10/main.js
- // search for fromLatLngToPoint and fromPointToLatLng
- private Point2D.Double pt(double lat, double lng) {
- return pt(lat, lng, coord_pt, scale_x, scale_y);
- }
-
- private static Point2D.Double pt(double lat, double lng,
- Point2D.Double centre, int zoom)
- {
- double scale_x = 256/360.0 * Math.pow(2, zoom);
- double scale_y = 256/(2.0*Math.PI) * Math.pow(2, zoom);
- return pt(lat, lng, centre, scale_x, scale_y);
- }
-
- private static Point2D.Double pt(double lat, double lng,
- Point2D.Double centre, double scale_x, double scale_y)
- {
- Point2D.Double res = new Point2D.Double();
- double e;
-
- res.x = centre.x + lng*scale_x;
- e = limit(Math.sin(Math.toRadians(lat)),-(1-1.0E-15),1-1.0E-15);
- res.y = centre.y + 0.5*Math.log((1+e)/(1-e))*-scale_y;
- return res;
- }
-
- private Point2D.Double latlng(double x, double y) {
- return latlng(new Point2D.Double(x,y), coord_pt);
- }
- private Point2D.Double latlng(Point2D.Double pt) {
- return latlng(pt, coord_pt);
- }
- private Point2D.Double latlng(Point2D.Double pt, Point2D.Double centre) {
- double lat, lng;
- double rads;
-
- lng = (pt.x - centre.x)/scale_x;
- rads = 2 * Math.atan(Math.exp((pt.y-centre.y)/-scale_y));
- lat = Math.toDegrees(rads - Math.PI/2);
-
- return new Point2D.Double(lat,lng);