commit
46284bdb37
@ -0,0 +1,167 @@
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/**
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* 判断经纬度是否超出中国境内
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*/
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function isLocationOutOfChina(latitude, longitude) {
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if (longitude < 72.004 || longitude > 137.8347 || latitude < 0.8293 || latitude > 55.8271)
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return true;
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return false;
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}
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/**
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* 将WGS-84(国际标准)转为GCJ-02(火星坐标):
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*/
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function transformFromWGSToGCJ(latitude, longitude) {
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var lat = "";
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var lon = "";
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var ee = 0.00669342162296594323;
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var a = 6378245.0;
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var pi = 3.14159265358979324;
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if (isLocationOutOfChina(latitude, longitude)) {
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lat = latitude;
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lon = longitude;
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} else {
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var adjustLat = transformLatWithXY(longitude - 105.0, latitude - 35.0);
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var adjustLon = transformLonWithXY(longitude - 105.0, latitude - 35.0);
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var radLat = latitude / 180.0 * pi;
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var magic = Math.sin(radLat);
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magic = 1 - ee * magic * magic;
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var sqrtMagic = Math.sqrt(magic);
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adjustLat = (adjustLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
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adjustLon = (adjustLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
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latitude = latitude + adjustLat;
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longitude = longitude + adjustLon;
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}
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return {
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latitude: latitude,
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longitude: longitude
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};
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}
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/**
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* 将GCJ-02(火星坐标)转为百度坐标:
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*/
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function transformFromGCJToBaidu(latitude, longitude) {
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var pi = 3.14159265358979324 * 3000.0 / 180.0;
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var z = Math.sqrt(longitude * longitude + latitude * latitude) + 0.00002 * Math.sin(latitude * pi);
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var theta = Math.atan2(latitude, longitude) + 0.000003 * Math.cos(longitude * pi);
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var a_latitude = (z * Math.sin(theta) + 0.006);
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var a_longitude = (z * Math.cos(theta) + 0.0065);
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return {
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latitude: a_latitude,
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longitude: a_longitude
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};
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}
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/**
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* 将百度坐标转为GCJ-02(火星坐标):
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*/
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function transformFromBaiduToGCJ(latitude, longitude) {
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var xPi = 3.14159265358979323846264338327950288 * 3000.0 / 180.0;
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var x = longitude - 0.0065;
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var y = latitude - 0.006;
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var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * xPi);
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var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * xPi);
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var a_latitude = z * Math.sin(theta);
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var a_longitude = z * Math.cos(theta);
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return {
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latitude: a_latitude,
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longitude: a_longitude
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};
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}
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/**
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* 将GCJ-02(火星坐标)转为WGS-84:
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*/
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function transformFromGCJToWGS(latitude, longitude) {
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var threshold = 0.00001;
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// The boundary
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var minLat = latitude - 0.5;
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var maxLat = latitude + 0.5;
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var minLng = longitude - 0.5;
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var maxLng = longitude + 0.5;
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var delta = 1;
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var maxIteration = 30;
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while (true) {
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var leftBottom = transformFromWGSToGCJ(minLat, minLng);
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var rightBottom = transformFromWGSToGCJ(minLat, maxLng);
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var leftUp = transformFromWGSToGCJ(maxLat, minLng);
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var midPoint = transformFromWGSToGCJ((minLat + maxLat) / 2, (minLng + maxLng) / 2);
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delta = Math.abs(midPoint.latitude - latitude) + Math.abs(midPoint.longitude - longitude);
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if (maxIteration-- <= 0 || delta <= threshold) {
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return {
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latitude: (minLat + maxLat) / 2,
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longitude: (minLng + maxLng) / 2
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};
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}
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if (isContains({
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latitude: latitude,
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longitude: longitude
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}, leftBottom, midPoint)) {
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maxLat = (minLat + maxLat) / 2;
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maxLng = (minLng + maxLng) / 2;
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} else if (isContains({
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latitude: latitude,
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longitude: longitude
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}, rightBottom, midPoint)) {
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maxLat = (minLat + maxLat) / 2;
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minLng = (minLng + maxLng) / 2;
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} else if (isContains({
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latitude: latitude,
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longitude: longitude
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}, leftUp, midPoint)) {
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minLat = (minLat + maxLat) / 2;
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maxLng = (minLng + maxLng) / 2;
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} else {
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minLat = (minLat + maxLat) / 2;
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minLng = (minLng + maxLng) / 2;
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}
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}
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}
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function isContains(point, p1, p2) {
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return (point.latitude >= Math.min(p1.latitude, p2.latitude) && point.latitude <= Math.max(p1.latitude, p2
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.latitude)) && (point.longitude >= Math.min(p1.longitude, p2.longitude) && point.longitude <= Math.max(p1
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.longitude, p2.longitude));
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}
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function transformLatWithXY(x, y) {
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var pi = 3.14159265358979324;
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var lat = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
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lat += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
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lat += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
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lat += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
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return lat;
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}
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function transformLonWithXY(x, y) {
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var pi = 3.14159265358979324;
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var lon = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
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lon += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
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lon += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
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lon += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
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return lon;
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}
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module.exports = {
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isLocationOutOfChina: isLocationOutOfChina,
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transformFromWGSToGCJ: transformFromWGSToGCJ,
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transformFromGCJToBaidu: transformFromGCJToBaidu,
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transformFromBaiduToGCJ: transformFromBaiduToGCJ,
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transformFromGCJToWGS: transformFromGCJToWGS
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}
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