// ==============坐标系转换===============
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var GSP = {
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PI: 3.14159265358979324,
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x_pi: 3.14159265358979324 * 3000.0 / 180.0,
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delta: function (lat, lon) {
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// Krasovsky 1940
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//
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// a = 6378245.0, 1/f = 298.3
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// b = a * (1 - f)
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// ee = (a^2 - b^2) / a^2;
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var a = 6378245.0 // a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
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var ee = 0.00669342162296594323 // ee: 椭球的偏心率。
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var dLat = this.transformLat(lon - 105.0, lat - 35.0)
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var dLon = this.transformLon(lon - 105.0, lat - 35.0)
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var radLat = lat / 180.0 * this.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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dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * this.PI)
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dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * this.PI)
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return { lat: dLat, lon: dLon }
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},
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// WGS-84 to GCJ-02
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gcj_encrypt: function (wgsLat, wgsLon) {
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if (this.outOfChina(wgsLat, wgsLon)) { return { lat: wgsLat, lon: wgsLon } }
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var d = this.delta(wgsLat, wgsLon)
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return { lat: wgsLat + d.lat, lon: wgsLon + d.lon }
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},
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// GCJ-02 to WGS-84
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gcj_decrypt: function (gcjLat, gcjLon) {
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if (this.outOfChina(gcjLat, gcjLon)) { return { lat: gcjLat, lon: gcjLon } }
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var d = this.delta(gcjLat, gcjLon)
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return { lat: gcjLat - d.lat, lon: gcjLon - d.lon }
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},
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// GCJ-02 to WGS-84 exactly
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gcj_decrypt_exact: function (gcjLat, gcjLon) {
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const initDelta = 0.01
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const threshold = 0.000000001
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let dLat = initDelta
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let dLon = initDelta
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let mLat = gcjLat - dLat
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let mLon = gcjLon - dLon
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let pLat = gcjLat + dLat
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let pLon = gcjLon + dLon
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let wgsLat
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let wgsLon
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let i = 0
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while (1) {
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wgsLat = (mLat + pLat) / 2
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wgsLon = (mLon + pLon) / 2
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var tmp = this.gcj_encrypt(wgsLat, wgsLon)
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dLat = tmp.lat - gcjLat
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dLon = tmp.lon - gcjLon
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if ((Math.abs(dLat) < threshold) && (Math.abs(dLon) < threshold)) { break }
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if (dLat > 0) pLat = wgsLat; else mLat = wgsLat
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if (dLon > 0) pLon = wgsLon; else mLon = wgsLon
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if (++i > 10000) break
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}
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// console.log(i);
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return { lat: wgsLat, lon: wgsLon }
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},
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// GCJ-02 to BD-09
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bd_encrypt: function (gcjLat, gcjLon) {
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const x = gcjLon
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const y = gcjLat
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const z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * this.x_pi)
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const theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * this.x_pi)
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const bdLon = z * Math.cos(theta) + 0.0065
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const bdLat = z * Math.sin(theta) + 0.006
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return { lat: bdLat, lon: bdLon }
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},
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// BD-09 to GCJ-02
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bd_decrypt: function (bdLat, bdLon) {
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const x = bdLon - 0.0065
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const y = bdLat - 0.006
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const z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * this.x_pi)
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const theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * this.x_pi)
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const gcjLon = z * Math.cos(theta)
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const gcjLat = z * Math.sin(theta)
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return { lat: gcjLat, lon: gcjLon }
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},
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// WGS-84 to Web mercator
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// mercatorLat -> y mercatorLon -> x
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mercator_encrypt: function (wgsLat, wgsLon) {
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const x = wgsLon * 20037508.34 / 180.0
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let y = Math.log(Math.tan((90.0 + wgsLat) * this.PI / 360.0)) / (this.PI / 180.0)
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y = y * 20037508.34 / 180.0
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return { lat: y, lon: x }
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/*
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if ((Math.abs(wgsLon) > 180 || Math.abs(wgsLat) > 90))
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return null;
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var x = 6378137.0 * wgsLon * 0.017453292519943295;
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var a = wgsLat * 0.017453292519943295;
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var y = 3189068.5 * Math.log((1.0 + Math.sin(a)) / (1.0 - Math.sin(a)));
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return {'lat' : y, 'lon' : x};
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// */
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},
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// Web mercator to WGS-84
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// mercatorLat -> y mercatorLon -> x
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mercator_decrypt: function (mercatorLat, mercatorLon) {
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var x = mercatorLon / 20037508.34 * 180.0
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var y = mercatorLat / 20037508.34 * 180.0
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y = 180 / this.PI * (2 * Math.atan(Math.exp(y * this.PI / 180.0)) - this.PI / 2)
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return { lat: y, lon: x }
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/*
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if (Math.abs(mercatorLon) < 180 && Math.abs(mercatorLat) < 90)
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return null;
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if ((Math.abs(mercatorLon) > 20037508.3427892) || (Math.abs(mercatorLat) > 20037508.3427892))
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return null;
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var a = mercatorLon / 6378137.0 * 57.295779513082323;
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var x = a - (Math.floor(((a + 180.0) / 360.0)) * 360.0);
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var y = (1.5707963267948966 - (2.0 * Math.atan(Math.exp((-1.0 * mercatorLat) / 6378137.0)))) * 57.295779513082323;
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return {'lat' : y, 'lon' : x};
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// */
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},
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// two point's distance
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distance: function (latA, lonA, latB, lonB) {
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var earthR = 6371000.0
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var x = Math.cos(latA * this.PI / 180.0) * Math.cos(latB * this.PI / 180.0) * Math.cos((lonA - lonB) * this.PI / 180)
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var y = Math.sin(latA * this.PI / 180.0) * Math.sin(latB * this.PI / 180.0)
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var s = x + y
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if (s > 1) s = 1
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if (s < -1) s = -1
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var alpha = Math.acos(s)
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var distance = alpha * earthR
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return distance
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},
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outOfChina: function (lat, lon) {
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if (lon < 72.004 || lon > 137.8347) { return true }
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if (lat < 0.8293 || lat > 55.8271) { return true }
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return false
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},
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transformLat: function (x, y) {
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var ret = -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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ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0
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ret += (20.0 * Math.sin(y * this.PI) + 40.0 * Math.sin(y / 3.0 * this.PI)) * 2.0 / 3.0
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ret += (160.0 * Math.sin(y / 12.0 * this.PI) + 320 * Math.sin(y * this.PI / 30.0)) * 2.0 / 3.0
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return ret
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},
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transformLon: function (x, y) {
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var ret = 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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ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0
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ret += (20.0 * Math.sin(x * this.PI) + 40.0 * Math.sin(x / 3.0 * this.PI)) * 2.0 / 3.0
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ret += (150.0 * Math.sin(x / 12.0 * this.PI) + 300.0 * Math.sin(x / 30.0 * this.PI)) * 2.0 / 3.0
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return ret
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}
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}
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export default {
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GSP
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}
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