GeometryUtil.js

(function () {

	var defaultPrecision = {
		km: 2,
		ha: 2,
		m: 0,
		mi: 2,
		ac: 2,
		yd: 0,
		ft: 0,
		nm: 2
	};


	/**
	 * @class L.GeometryUtil
	 * @aka GeometryUtil
	 */
	L.GeometryUtil = L.extend(L.GeometryUtil || {}, {
		// Ported from the OpenLayers implementation. See https://github.com/openlayers/openlayers/blob/master/lib/OpenLayers/Geometry/LinearRing.js#L270

		// @method geodesicArea(): number
		geodesicArea: function (latLngs) {
			var pointsCount = latLngs.length,
				area = 0.0,
				d2r = Math.PI / 180,
				p1, p2;

			if (pointsCount > 2) {
				for (var i = 0; i < pointsCount; i++) {
					p1 = latLngs[i];
					p2 = latLngs[(i + 1) % pointsCount];
					area += ((p2.lng - p1.lng) * d2r) *
						(2 + Math.sin(p1.lat * d2r) + Math.sin(p2.lat * d2r));
				}
				area = area * 6378137.0 * 6378137.0 / 2.0;
			}

			return Math.abs(area);
		},

		// @method formattedNumber(n, precision): string
		// Returns n in specified number format (if defined) and precision
		formattedNumber: function (n, precision) {
			var formatted = parseFloat(n).toFixed(precision),
				format = L.drawLocal.format && L.drawLocal.format.numeric,
				delimiters = format && format.delimiters,
				thousands = delimiters && delimiters.thousands,
				decimal = delimiters && delimiters.decimal;

			if (thousands || decimal) {
				var splitValue = formatted.split('.');
				formatted = thousands ? splitValue[0].replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1' + thousands) : splitValue[0];
				decimal = decimal || '.';
				if (splitValue.length > 1) {
					formatted = formatted + decimal + splitValue[1];
				}
			}

			return formatted;
		},

		// @method readableArea(area, isMetric, precision): string
		// Returns a readable area string in yards or metric.
		// The value will be rounded as defined by the precision option object.
		readableArea: function (area, isMetric, precision) {
			var areaStr,
				units,
				precision = L.Util.extend({}, defaultPrecision, precision);

			if (isMetric) {
				units = ['ha', 'm'];
				type = typeof isMetric;
				if (type === 'string') {
					units = [isMetric];
				} else if (type !== 'boolean') {
					units = isMetric;
				}

				if (area >= 1000000 && units.indexOf('km') !== -1) {
					areaStr = L.GeometryUtil.formattedNumber(area * 0.000001, precision['km']) + ' km²';
				} else if (area >= 10000 && units.indexOf('ha') !== -1) {
					areaStr = L.GeometryUtil.formattedNumber(area * 0.0001, precision['ha']) + ' ha';
				} else {
					areaStr = L.GeometryUtil.formattedNumber(area, precision['m']) + ' m²';
				}
			} else {
				area /= 0.836127; // Square yards in 1 meter

				if (area >= 3097600) { //3097600 square yards in 1 square mile
					areaStr = L.GeometryUtil.formattedNumber(area / 3097600, precision['mi']) + ' mi²';
				} else if (area >= 4840) { //4840 square yards in 1 acre
					areaStr = L.GeometryUtil.formattedNumber(area / 4840, precision['ac']) + ' acres';
				} else {
					areaStr = L.GeometryUtil.formattedNumber(area, precision['yd']) + ' yd²';
				}
			}

			return areaStr;
		},

		// @method readableDistance(distance, units): string
		// Converts a metric distance to one of [ feet, nauticalMile, metric or yards ] string
		//
		// @alternative
		// @method readableDistance(distance, isMetric, useFeet, isNauticalMile, precision): string
		// Converts metric distance to distance string.
		// The value will be rounded as defined by the precision option object.
		readableDistance: function (distance, isMetric, isFeet, isNauticalMile, precision) {
			var distanceStr,
				units,
				precision = L.Util.extend({}, defaultPrecision, precision);

			if (isMetric) {
				units = typeof isMetric == 'string' ? isMetric : 'metric';
			} else if (isFeet) {
				units = 'feet';
			} else if (isNauticalMile) {
				units = 'nauticalMile';
			} else {
				units = 'yards';
			}

			switch (units) {
				case 'metric':
					// show metres when distance is < 1km, then show km
					if (distance > 1000) {
						distanceStr = L.GeometryUtil.formattedNumber(distance / 1000, precision['km']) + ' km';
					} else {
						distanceStr = L.GeometryUtil.formattedNumber(distance, precision['m']) + ' m';
					}
					break;
				case 'feet':
					distance *= 1.09361 * 3;
					distanceStr = L.GeometryUtil.formattedNumber(distance, precision['ft']) + ' ft';

					break;
				case 'nauticalMile':
					distance *= 0.53996;
					distanceStr = L.GeometryUtil.formattedNumber(distance / 1000, precision['nm']) + ' nm';
					break;
				case 'yards':
				default:
					distance *= 1.09361;

					if (distance > 1760) {
						distanceStr = L.GeometryUtil.formattedNumber(distance / 1760, precision['mi']) + ' miles';
					} else {
						distanceStr = L.GeometryUtil.formattedNumber(distance, precision['yd']) + ' yd';
					}
					break;
			}
			return distanceStr;
		},

		// @method isVersion07x(): boolean
		// Returns true if the Leaflet version is 0.7.x, false otherwise.
		isVersion07x: function () {
			var version = L.version.split('.');
			//If Version is == 0.7.*
			return parseInt(version[0], 10) === 0 && parseInt(version[1], 10) === 7;
		},
	});

})();