|
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var forEachPoint = function (func) {
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return function (input, opt_output, opt_dimension) {
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var len = input.length;
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var dimension = opt_dimension ? opt_dimension : 2;
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var output;
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if (opt_output) {
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output = opt_output;
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} else {
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if (dimension !== 2) {
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output = input.slice();
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} else {
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output = new Array(len);
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}
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}
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for (var offset = 0; offset < len; offset += dimension) {
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func(input, output, offset);
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}
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return output;
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};
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};
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var gcj02 = {};
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var i = 0;
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var PI = Math.PI;
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var AXIS = 6378245.0;
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var OFFSET = 0.00669342162296594323; // (a^2 - b^2) / a^2
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function delta(wgLon, wgLat) {
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var dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
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var dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
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var radLat = (wgLat / 180.0) * PI;
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var magic = Math.sin(radLat);
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magic = 1 - OFFSET * magic * magic;
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var sqrtMagic = Math.sqrt(magic);
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dLat = (dLat * 180.0) / (((AXIS * (1 - OFFSET)) / (magic * sqrtMagic)) * PI);
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dLon = (dLon * 180.0) / ((AXIS / sqrtMagic) * Math.cos(radLat) * PI);
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return [dLon, dLat];
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}
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function outOfChina(lon, lat) {
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if (lon < 72.004 || lon > 137.8347) {
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return true;
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}
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if (lat < 0.8293 || lat > 55.8271) {
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return true;
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}
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return false;
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}
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function transformLat(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 * PI) + 20.0 * Math.sin(2.0 * x * PI)) * 2.0) / 3.0;
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ret += ((20.0 * Math.sin(y * PI) + 40.0 * Math.sin((y / 3.0) * PI)) * 2.0) / 3.0;
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ret += ((160.0 * Math.sin((y / 12.0) * PI) + 320 * Math.sin((y * PI) / 30.0)) * 2.0) / 3.0;
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return ret;
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}
|
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function transformLon(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 * PI) + 20.0 * Math.sin(2.0 * x * PI)) * 2.0) / 3.0;
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ret += ((20.0 * Math.sin(x * PI) + 40.0 * Math.sin((x / 3.0) * PI)) * 2.0) / 3.0;
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ret += ((150.0 * Math.sin((x / 12.0) * PI) + 300.0 * Math.sin((x / 30.0) * PI)) * 2.0) / 3.0;
|
return ret;
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}
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gcj02.toWGS84 = forEachPoint(function (input, output, offset) {
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var lng = input[offset];
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var lat = input[offset + 1];
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if (!outOfChina(lng, lat)) {
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var deltaD = delta(lng, lat);
|
lng = lng - deltaD[0];
|
lat = lat - deltaD[1];
|
}
|
output[offset] = lng;
|
output[offset + 1] = lat;
|
});
|
|
gcj02.fromWGS84 = forEachPoint(function (input, output, offset) {
|
var lng = input[offset];
|
var lat = input[offset + 1];
|
if (!outOfChina(lng, lat)) {
|
var deltaD = delta(lng, lat);
|
lng = lng + deltaD[0];
|
lat = lat + deltaD[1];
|
}
|
output[offset] = lng;
|
output[offset + 1] = lat;
|
});
|
|
var sphericalMercator = {};
|
|
var RADIUS = 6378137;
|
var MAX_LATITUDE = 85.0511287798;
|
var RAD_PER_DEG = Math.PI / 180;
|
|
sphericalMercator.forward = forEachPoint(function (input, output, offset) {
|
var lat = Math.max(Math.min(MAX_LATITUDE, input[offset + 1]), -MAX_LATITUDE);
|
var sin = Math.sin(lat * RAD_PER_DEG);
|
|
output[offset] = RADIUS * input[offset] * RAD_PER_DEG;
|
output[offset + 1] = (RADIUS * Math.log((1 + sin) / (1 - sin))) / 2;
|
});
|
|
sphericalMercator.inverse = forEachPoint(function (input, output, offset) {
|
output[offset] = input[offset] / RADIUS / RAD_PER_DEG;
|
output[offset + 1] = (2 * Math.atan(Math.exp(input[offset + 1] / RADIUS)) - Math.PI / 2) / RAD_PER_DEG;
|
});
|
|
var projzh = {};
|
projzh.ll2gmerc = function (input, opt_output, opt_dimension) {
|
let output = gcj02.fromWGS84(input, opt_output, opt_dimension);
|
return projzh.ll2smerc(output, output, opt_dimension);
|
};
|
projzh.gmerc2ll = function (input, opt_output, opt_dimension) {
|
let output = projzh.smerc2ll(input, input, opt_dimension);
|
return gcj02.toWGS84(output, opt_output, opt_dimension);
|
};
|
projzh.smerc2gmerc = function (input, opt_output, opt_dimension) {
|
let output = projzh.smerc2ll(input, input, opt_dimension);
|
output = gcj02.fromWGS84(output, output, opt_dimension);
|
return projzh.ll2smerc(output, output, opt_dimension);
|
};
|
projzh.gmerc2smerc = function (input, opt_output, opt_dimension) {
|
let output = projzh.smerc2ll(input, input, opt_dimension);
|
output = gcj02.toWGS84(output, output, opt_dimension);
|
return projzh.ll2smerc(output, output, opt_dimension);
|
};
|
|
projzh.ll2smerc = sphericalMercator.forward;
|
projzh.smerc2ll = sphericalMercator.inverse;
|
|
// 定义GCJ02
|
const gcj02Extent = [-20037508.342789244, -20037508.342789244, 20037508.342789244, 20037508.342789244];
|
const gcj02Mecator = new ol.proj.Projection({
|
code: 'GCJ-02',
|
extent: gcj02Extent,
|
units: 'm',
|
});
|
ol.proj.addProjection(gcj02Mecator);
|
// 将4326/3857转为gcj02坐标的方法定义
|
ol.proj.addCoordinateTransforms('EPSG:4326', gcj02Mecator, projzh.ll2gmerc, projzh.gmerc2ll);
|
ol.proj.addCoordinateTransforms('EPSG:3857', gcj02Mecator, projzh.smerc2gmerc, projzh.gmerc2smerc);
|
|
// 我使用的react，所以这里需要导出定义的gcj02Mecator，提供给外部使用
|
export default gcj02Mecator;
|
