/src/geo/LatLng.js

/*

	CM.LatLng represents a geographical point with latitude and longtitude coordinates.

*/



L.LatLng = function (/*Number*/ rawLat, /*Number*/ rawLng, /*Boolean*/ noWrap) {

	var lat = parseFloat(rawLat),

		lng = parseFloat(rawLng);



	if (isNaN(lat) || isNaN(lng)) {

		throw new Error('Invalid LatLng object: (' + rawLat + ', ' + rawLng + ')');

	}



	if (noWrap !== true) {

		lat = Math.max(Math.min(lat, 90), -90);					// clamp latitude into -90..90

		lng = (lng + 180) % 360 + ((lng < -180 || lng === 180) ? 180 : -180);	// wrap longtitude into -180..180

	}



	//TODO change to lat() & lng()

	this.lat = lat;

	this.lng = lng;

};



L.Util.extend(L.LatLng, {

	DEG_TO_RAD: Math.PI / 180,

	RAD_TO_DEG: 180 / Math.PI,

	MAX_MARGIN: 1.0E-9 // max margin of error for the "equals" check

});



L.LatLng.prototype = {

	equals: function (/*LatLng*/ obj) {

		if (!(obj instanceof L.LatLng)) {

			return false;

		}



		var margin = Math.max(Math.abs(this.lat - obj.lat), Math.abs(this.lng - obj.lng));

		return margin <= L.LatLng.MAX_MARGIN;

	},



	toString: function () {

		return 'LatLng(' +

				L.Util.formatNum(this.lat) + ', ' +

				L.Util.formatNum(this.lng) + ')';

	},



	// Haversine distance formula, see http://en.wikipedia.org/wiki/Haversine_formula

	distanceTo: function (/*LatLng*/ other)/*->Double*/ {

		var R = 6378137, // earth radius in meters

			d2r = L.LatLng.DEG_TO_RAD,

			dLat = (other.lat - this.lat) * d2r,

			dLon = (other.lng - this.lng) * d2r,

			lat1 = this.lat * d2r,

			lat2 = other.lat * d2r,

			sin1 = Math.sin(dLat / 2),

			sin2 = Math.sin(dLon / 2);



		var a = sin1 * sin1 + sin2 * sin2 * Math.cos(lat1) * Math.cos(lat2);



		return R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

	}

};