+ },
+
+ zoomPrecision: function (zoom) {
+ var pixels = Math.pow(2, 8 + zoom);
+ var degrees = 180;
+ return Math.ceil(Math.log10(pixels / degrees));
+ },
+
+ cropLocation: function (latLng, zoom) {
+ const precision = OSM.zoomPrecision(zoom),
+ wrapped = latLng.wrap();
+ return [wrapped.lat, wrapped.lng].map(c => c.toFixed(precision));
+ },
+
+ locationCookie: function (map) {
+ const zoom = map.getZoom(),
+ center = OSM.cropLocation(map.getCenter(), zoom).reverse();
+ return [...center, 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)
+ ));