地图通用方法

通用方法

计算地图中心点

/**
 * @params path:坐标点数组 二维数组 [[x,y],[x,y]]
 * return 中心点坐标数组[x,y]
 */
function getCenterPoint(path) {
    var x = 0.0;
    var y = 0.0;
    for (var i = 0; i < path.length; i++) {
        x = x + parseFloat(path[i][0]);
        y = y + parseFloat(path[i][1]);
    }
    x = x / path.length;
    y = y / path.length;
    return [x,y]
}

判断坐标是否在国内

export function outOfChina(lon, lat) {
  if ((lon < 72.004 || lon > 137.8347) && (lat < 0.8293 || lat > 55.8271)) {
    return true
  } else {
    return false
  }
}

判断点是否在多边形，圆内部

/**

    判断一个点是否在多边形内部

    @param points 多边形坐标集合

    @param testPoint 测试点坐标

    返回true为真，false为假

*/
 export function insidePolygon(points, testPoint) {
    var x = testPoint[0], y = testPoint[1];
    var inside = false;
    for (var i = 0, j = points.length - 1; i < points.length; j = i++) {
        var xi = points[i][0], yi = points[i][1];
        var xj = points[j][0], yj = points[j][1];

        var intersect = ((yi > y) != (yj > y))
            && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
        if (intersect) inside = !inside;
    }
    return inside;
}

/**

判断一个点是否在圆的内部
@param point 测试点坐标
@param circle 圆心坐标
@param r 圆半径
返回true为真，false为假
*/
export function pointInsideCircle(point, circle, r) {
    if (r === 0) return false
    var dx = circle[0] - point[0]
    var dy = circle[1] - point[1]
    return dx * dx + dy * dy <= r * r
}

根据经纬度计算距离

// 经纬度转换成三角函数中度分表形式。
function rad(d) {
    return d * Math.PI / 180.0; 
}


// 根据经纬度计算距离，参数分别为第一点的纬度，经度；第二点的纬度，经度 返回千米数
export function getDistance(lat1, lng1, lat2, lng2) {
    // console.info(lat1, lng1, lat2, lng2)

    var radLat1 = rad(lat1);
    var radLat2 = rad(lat2);
    var a = radLat1 - radLat2;
    var b = rad(lng1) - rad(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 * 6378.137; // EARTH_RADIUS;
    s = Math.round(s * 10000) / 10000; //输出为公里

    var distance = s;
    var distance_str = "";

    if (parseInt(distance) >= 1) {
        distance_str = distance.toFixed(1) + "km";
    } else {
        distance_str = distance * 1000 + "m";
    }

    //s=s.toFixed(4);

    // console.info('lyj 距离是', s);
    // console.info('lyj 距离是', distance_str);
    return s;checkDistance
}

转坐标通用方法

84 火星坐标互转

const pi = 3.14159265358979324
const a = 6378245.0
const ee = 0.00669342162296594323
// 84转火星
export function earthToMars(lat, lng) {
  function transformLat(x, y) {
    let ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x))
    ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0
    ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0
    ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0
    return ret
  }

  function transformLon(x, y) {
    let ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x))
    ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0
    ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0
    ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0
    return ret
  }

  function transform(wgLat, wgLon) {
    const mars_point = { lon: 0, lat: 0 }
    // if (outOfChina(wgLat, wgLon)) {
    //   mars_point.lat = wgLat
    //   mars_point.lon = wgLon
    //   return
    // }
    let dLat = transformLat(wgLon - 105.0, wgLat - 35.0)
    let dLon = transformLon(wgLon - 105.0, wgLat - 35.0)
    const radLat = wgLat / 180.0 * pi
    let magic = Math.sin(radLat)
    magic = 1 - ee * magic * magic
    const sqrtMagic = Math.sqrt(magic)
    dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi)
    dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi)
    mars_point.lat = wgLat + dLat
    mars_point.lon = wgLon + dLon
    return mars_point
  }

  return transform(lat, lng)
}

// 火星转84
export function marsToEarth(lat, lng) {
  function transformGCJ2WGS(gcjLat, gcjLon) {
    let d = delta(gcjLat, gcjLon)
    return {
      'lat': gcjLat - d.lat,
      'lon': gcjLon - d.lon
    }
  }
  function delta(lat, lon) {
    let 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。
    let ee = 0.00669342162296594323 //  ee: 椭球的偏心率。
    let dLat = transformLat(lon - 105.0, lat - 35.0)
    let dLon = transformLon(lon - 105.0, lat - 35.0)
    let radLat = lat / 180.0 * pi
    let magic = Math.sin(radLat)
    magic = 1 - ee * magic * magic
    let sqrtMagic = Math.sqrt(magic)
    dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi)
    dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi)
    return {
      'lat': dLat,
      'lon': dLon
    }
  }
  function transformLat(x, y) {
    let ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x))
    ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0
    ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0
    ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0
    return ret
  }
  function transformLon(x, y) {
    let ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x))
    ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0
    ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0
    ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0
    return ret
  }
  return transformGCJ2WGS(lat, lng)
}