+ },
+
+ zoomPrecision: function(zoom) {
+ return Math.max(0, Math.ceil(Math.log(zoom) / Math.LN2));
+ },
+
+ 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)
+ ));