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40 lines
1.1 KiB
40 lines
1.1 KiB
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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|
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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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}; |