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用JavaScript计算两点经纬度距离

用JavaScript计算两点经纬度距离

作者: 小小的开发人员 | 来源:发表于2019-05-17 16:14 被阅读0次

    计算地球表面两点间的距离大概有两种办法。

    第一种是默认地球是一个光滑的球面,然后计算任意两点间的距离,这个距离叫做大圆距离(The Great Circle Distance):

    var EARTH_RADIUS = 6378137.0;    //单位m
        var PI = Math.PI;
        
        function getRad(d){
            return d*PI/180.0;
        }
    
        function getGreatCircleDistance(lat1,lng1,lat2,lng2){
            var radLat1 = getRad(lat1);
            var radLat2 = getRad(lat2);
            
            var a = radLat1 - radLat2;
            var b = getRad(lng1) - getRad(lng2);
            
            var s = 2*Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) + Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
            s = s*EARTH_RADIUS;
            s = Math.round(s*10000)/10000.0;
                    
            return s;
        }
    

    地球并不是一个真正的圆球体,而是椭球,有了下面的公式:

    /** 计算两经纬度之间的距离,单位是m
    * approx distance between two points on earth ellipsoid
    */
    function getFlatternDistance (lat1, lng1, lat2, lng2) {
      const PI = Math.PI
      const EARTH_RADIUS = 6378137.0
      function getRad (d) {
        return d * PI / 180.0
      }
      let f = getRad((lat1 + lat2) / 2)
      let g = getRad((lat1 - lat2) / 2)
      let l = getRad((lng1 - lng2) / 2)
      let sg = Math.sin(g)
      let sl = Math.sin(l)
      let sf = Math.sin(f)
    
      let s, c, w, r, d, h1, h2
      let a = EARTH_RADIUS
      let fl = 1 / 298.257
    
      sg = sg * sg
      sl = sl * sl
      sf = sf * sf
    
      s = sg * (1 - sl) + (1 - sf) * sl
      c = (1 - sg) * (1 - sl) + sf * sl
    
      w = Math.atan(Math.sqrt(s / c))
      r = Math.sqrt(s * c) / w
      d = 2 * w * a
      h1 = (3 * r - 1) / 2 / c
      h2 = (3 * r + 1) / 2 / s
    
      return d * (1 + fl * (h1 * sf * (1 - sg) - h2 * (1 - sf) * sg))
    }
    
    精度比较

    提供一个在线计算经纬度的网站:http://www.hhlink.com/%E7%BB%8F%E7%BA%AC%E5%BA%A6/

    let EARTH_RADIUS = 6378137.0;    //单位m
    let PI = Math.PI;
    
    function getRad(d){
        return d*PI/180.0;
    }
    
    function getGreatCircleDistance(lat1,lng1,lat2,lng2){
        let radLat1 = getRad(lat1);
        let radLat2 = getRad(lat2);
    
        let a = radLat1 - radLat2;
        let b = getRad(lng1) - getRad(lng2);
    
        let s = 2*Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) + Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
        s = s*EARTH_RADIUS;
        s = Math.round(s*10000)/10000.0;
    
        return s;
    }
    
    /** 计算两经纬度之间的距离,单位是m
     * approx distance between two points on earth ellipsoid
     */
    function getFlatternDistance (lat1, lng1, lat2, lng2) {
        const PI = Math.PI
        const EARTH_RADIUS = 6378137.0
        function getRad (d) {
            return d * PI / 180.0
        }
        let f = getRad((lat1 + lat2) / 2)
        let g = getRad((lat1 - lat2) / 2)
        let l = getRad((lng1 - lng2) / 2)
        let sg = Math.sin(g)
        let sl = Math.sin(l)
        let sf = Math.sin(f)
    
        let s, c, w, r, d, h1, h2
        let a = EARTH_RADIUS
        let fl = 1 / 298.257
    
        sg = sg * sg
        sl = sl * sl
        sf = sf * sf
    
        s = sg * (1 - sl) + (1 - sf) * sl
        c = (1 - sg) * (1 - sl) + sf * sl
    
        w = Math.atan(Math.sqrt(s / c))
        r = Math.sqrt(s * c) / w
        d = 2 * w * a
        h1 = (3 * r - 1) / 2 / c
        h2 = (3 * r + 1) / 2 / s
    
        return d * (1 + fl * (h1 * sf * (1 - sg) - h2 * (1 - sf) * sg))
    }
    
    let result1 = getGreatCircleDistance(30.1234, 140.1234, 30.3456, 140.3456)
    let result2 = getFlatternDistance(30.1234, 140.1234, 30.3456, 140.3456)
    console.log(result1) // 32688.3298
    console.log(result2) // 32622.43244078783
    
    
    

    可以看到两种方法计算出的距离还是比较接近的,做项目时我也跟后台开发确认过,他的计算结果与第二种计算方法吻合度好。

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