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40 lines
1.1 KiB
40 lines
1.1 KiB
4 years ago
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const isPointInPolygon =(aLat, aLon, pointList)=> {
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/*
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:param aLon: double 经度
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:param aLat: double 纬度
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:param pointList: list [{latitude: 22.22, longitude: 113.113}...] 多边形点的顺序需根据顺时针或逆时针，不能乱
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*/
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var iSum = 0
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var iCount = pointList.length
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if(iCount < 3) {
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return false
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}
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for(var i = 0; i < iCount;i++) {
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var pLat1 = pointList[i][1]
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var pLon1 = pointList[i][0]
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if(i == iCount - 1) {
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var pLat2 = pointList[0][1]
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var pLon2 = pointList[0][0]
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} else {
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var pLat2 = pointList[i + 1][1]
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var pLon2 = pointList[i + 1][0]
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}
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if (((aLat >= pLat1) && (aLat < pLat2)) || ((aLat>=pLat2) && (aLat < pLat1))) {
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if (Math.abs(pLat1 - pLat2) > 0) {
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var pLon = pLon1 - ((pLon1 - pLon2) * (pLat1 - aLat)) / (pLat1 - pLat2);
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if(pLon < aLon) {
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iSum += 1
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}
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}
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}
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}
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if(iSum % 2 != 0) {
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return true
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}else {
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return false
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}
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}
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module.exports = {
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isPointInPolygon,
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};
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