+ var center, zoom, layers;
+
+ if (args instanceof L.Map) {
+ center = args.getCenter();
+ zoom = args.getZoom();
+ layers = args.getLayersCode();
+ } else {
+ center = args.center || L.latLng(args.lat, args.lon);
+ zoom = args.zoom;
+ layers = args.layers || '';
+ }
+
+ center = center.wrap();
+ layers = layers.replace('M', '');
+
+ var precision = OSM.zoomPrecision(zoom),
+ hash = '#map=' + zoom +
+ '/' + center.lat.toFixed(precision) +
+ '/' + center.lng.toFixed(precision);
+
+ if (layers) {
+ hash += '&layers=' + layers;
+ }
+
+ return hash;
+ },
+
+ zoomPrecision: function(zoom) {
+ var pixels = Math.pow(2, 8 + zoom);
+ var degrees = 180;
+ return Math.ceil(Math.log10(pixels / degrees));
+ },
+
+ locationCookie: function(map) {
+ var center = map.getCenter().wrap(),
+ zoom = map.getZoom(),
+ precision = OSM.zoomPrecision(zoom);
+ return [center.lng.toFixed(precision), center.lat.toFixed(precision), zoom, map.getLayersCode()].join('|');
+ },
+
+ distance: function(latlng1, latlng2) {
+ var lat1 = latlng1.lat * Math.PI / 180,
+ lng1 = latlng1.lng * Math.PI / 180,
+ lat2 = latlng2.lat * Math.PI / 180,
+ lng2 = latlng2.lng * Math.PI / 180,
+ latdiff = lat2 - lat1,
+ lngdiff = lng2 - lng1;
+
+ return 6372795 * 2 * Math.asin(
+ Math.sqrt(
+ Math.pow(Math.sin(latdiff / 2), 2) +
+ Math.cos(lat1) * Math.cos(lat2) * Math.pow(Math.sin(lngdiff / 2), 2)
+ ));