百度地图API画多边型，测面积

效果：

 

脚本：

"-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">



"Content-Type" content="text/html; charset=gb2312" />
耕地分布图
"text/javascript" src="http://api.map.baidu.com/api?v=1.3">
"Js/jquery-1.3.2.js" type="text/javascript">
"Js/GeoUtils.js" type="text/javascript">
"text/css">
  html,body
    {
        height:100%;
        margin:0;
    }




"width:100%; height:100%;z-index:9;border:1px solid gray" id="container">

    

    

    

"text/javascript">    

    var map = new BMap.Map("container", { mapType: BMAP_HYBRID_MAP });      //设置卫星图为底图    

    map.centerAndZoom(new BMap.Point(112.244629, 32.094896), 15);                     // 初始化地图,设置中心点坐标和地图级别。    

    map.enableScrollWheelZoom();                            //启用滚轮放大缩小    

    map.addControl(new BMap.NavigationControl());  //添加鱼骨控件    

    map.addControl(new BMap.MapTypeControl());          //添加地图类型控件    

    map.setCurrentCity("襄阳");          // 设置3D地图显示的城市 此项是必须设置的    

    

    

    fun(1, "112.254474,32.088357", "new BMap.Point(112.25221,32.091263),new BMap.Point(112.252785,32.091202),new BMap.Point(112.252929,32.090621),new BMap.Point(112.253576,32.090407),new BMap.Point(112.253576,32.090896),new BMap.Point(112.256199,32.090468),new BMap.Point(112.256558,32.091416),new BMap.Point(112.258319,32.091355),new BMap.Point(112.256055,32.085114),new BMap.Point(112.254007,32.085451),new BMap.Point(112.252785,32.085512),new BMap.Point(112.252282,32.085145),new BMap.Point(112.251851,32.085145),new BMap.Point(112.251635,32.084625),new BMap.Point(112.251025,32.084533),new BMap.Point(112.252138,32.091018)", '已播', 'green');    

    fun(2, "112.244543,32.085696", "new BMap.Point(112.24086,32.087332),new BMap.Point(112.244561,32.087669),new BMap.Point(112.248065,32.087791),new BMap.Point(112.248658,32.087883),new BMap.Point(112.249125,32.086047),new BMap.Point(112.24952,32.086063),new BMap.Point(112.250023,32.084258),new BMap.Point(112.241435,32.082973),new BMap.Point(112.240609,32.084548)", '未播', 'blue');    

    fun(3, "112.248244,32.088342", "new BMap.Point(112.247737,32.087975),new BMap.Point(112.248442,32.089149),new BMap.Point(112.248536,32.089149),new BMap.Point(112.248572,32.088036)", '未播', 'green');    

    

    //变量名,标签坐标,多边形坐标,文本,边框颜色    

    function fun(i,xy,arr,wb,ys) {    

        //创建经纬度数组    

        eval("var secRingCenter" + i+" = new BMap.Point("+xy+")");    

        eval("var secRing"+i+" = ["+arr+"]");    

        //创建多边形    

        eval("var secRingPolygon" + i + "= new BMap.Polygon(secRing" + i + ", { strokeColor: \"" + ys + "\", strokeWeight: 4})");    

        //eval("var secRingPolygon" + i + "= new BMap.Polygon(secRing" + i + ", { FillColor:\"red\", strokeColor: \"blue\", strokeWeight: 2, strokeOpacity: 0.3 })");    

    

        //添加多边形到地图上    

        map.addOverlay(eval("secRingPolygon"+i));    

    

        var resultArea = BMapLib.GeoUtils.getPolygonArea(eval("secRingPolygon" + i)); //计算多边形的面积（单位米）    

    

        //给多边形添加鼠标事件    

        eval("secRingPolygon"+i).addEventListener("mouseover", function () {//鼠标经过时    

            eval("secRingPolygon" + i).setStrokeColor("red"); //多边形边框为红色    

            //eval("secRingPolygon" + i).setFillColor(ys);     

            map.addOverlay(eval("secRingLabel"+i)); //添加多边形遮照    

            //map.panTo(eval("secRingCenter"+i)); //将地图移动到指定点    

        });    

        eval("secRingPolygon"+i).addEventListener("mouseout", function () {    

            eval("secRingPolygon" + i).setStrokeColor(ys);    

            //eval("secRingPolygon" + i).setFillColor("");     

            map.removeOverlay(eval("secRingLabel"+i));    

        });    

        eval("secRingPolygon"+i).addEventListener("click", function () {    

            map.zoomIn();    

            eval("secRingPolygon" + i).setStrokeColor(ys);    

            //eval("secRingPolygon" + i).setFillColor("");     

            map.setCenter(eval("secRingCenter"+i));    

        });    

        //创建标签    

        eval("var secRingLabel" + i + "= new BMap.Label(\"" + wb + " 面积(㎡)：" + Math.floor(resultArea) + "\", { offset: new BMap.Size(0, 0), position: secRingCenter" + i + "})");    

        eval("secRingLabel"+i).setStyle({ "z-index": "999999", "padding": "2px",  "border": "1px solid #ccff00" });    

    }    

    

GeoUtils.js

 

/**
* @fileoverview GeoUtils类提供若干几何算法，用来帮助用户判断点与矩形、
* 圆形、多边形线、多边形面的关系,并提供计算折线长度和多边形的面积的公式。
* 主入口类是GeoUtils，
* 基于Baidu Map API 1.2。
*
* @author Baidu Map Api Group
* @version 1.2
*/

//BMapLib.GeoUtils.degreeToRad(Number)
//将度转化为弧度

//BMapLib.GeoUtils.getDistance(Point, Point)
//计算两点之间的距离,两点坐标必须为经纬度

//BMapLib.GeoUtils.getPolygonArea(polygon)
//计算多边形面或点数组构建图形的面积,注意：坐标类型只能是经纬度，且不适合计算自相交多边形的面积(封闭的面积)

//BMapLib.GeoUtils.getPolylineDistance(polyline)
//计算折线或者点数组的长度

//BMapLib.GeoUtils.isPointInCircle(point, circle)
//判断点是否在圆形内

//BMapLib.GeoUtils.isPointInPolygon(point, polygon)
//判断点是否多边形内

//BMapLib.GeoUtils.isPointInRect(point, bounds)
//判断点是否在矩形内

//BMapLib.GeoUtils.isPointOnPolyline(point, polyline)
//判断点是否在折线上

//BMapLib.GeoUtils.radToDegree(Number)
//将弧度转化为度

/**
* @namespace BMap的所有library类均放在BMapLib命名空间下
*/
var BMapLib = window.BMapLib = BMapLib || {};
(function () {

    /**
    * 地球半径
    */
    var EARTHRADIUS = 6370996.81;

    /**
    * @exports GeoUtils as BMapLib.GeoUtils
    */
    var GeoUtils =
    /**
    * GeoUtils类，静态类，勿需实例化即可使用
    * @class GeoUtils类的入口。
    * 该类提供的都是静态方法，勿需实例化即可使用。
    */
     BMapLib.GeoUtils = function () {
     }

    /**
    * 判断点是否在矩形内
    * @param {Point} point 点对象
    * @param {Bounds} bounds 矩形边界对象
    * @returns {Boolean} 点在矩形内返回true,否则返回false
    */
    GeoUtils.isPointInRect = function (point, bounds) {
        //检查类型是否正确
        if (!(point instanceof BMap.Point) ||
             !(bounds instanceof BMap.Bounds)) {
            return false;
        }
        var sw = bounds.getSouthWest(); //西南脚点
        var ne = bounds.getNorthEast(); //东北脚点
        return (point.lng >= sw.lng && point.lng <= ne.lng && point.lat >= sw.lat && point.lat <= ne.lat);
    }

    /**
    * 判断点是否在圆形内
    * @param {Point} point 点对象
    * @param {Circle} circle 圆形对象
    * @returns {Boolean} 点在圆形内返回true,否则返回false
    */
    GeoUtils.isPointInCircle = function (point, circle) {
        //检查类型是否正确
        if (!(point instanceof BMap.Point) ||
            !(circle instanceof BMap.Circle)) {
            return false;
        }

        //point与圆心距离小于圆形半径，则点在圆内，否则在圆外
        var c = circle.getCenter();
        var r = circle.getRadius();

        var dis = GeoUtils.getDistance(point, c);
        if (dis <= r) {
            return true;
        } else {
            return false;
        }
    }

    /**
    * 判断点是否在折线上
    * @param {Point} point 点对象
    * @param {Polyline} polyline 折线对象
    * @returns {Boolean} 点在折线上返回true,否则返回false
    */
    GeoUtils.isPointOnPolyline = function (point, polyline) {
        //检查类型
        if (!(point instanceof BMap.Point) ||
             !(polyline instanceof BMap.Polyline)) {
            return false;
        }

        //首先判断点是否在线的外包矩形内，如果在，则进一步判断，否则返回false
        var lineBounds = polyline.getBounds();
        if (!this.isPointInRect(point, lineBounds)) {
            return false;
        }

        //判断点是否在线段上，设点为Q，线段为P1P2 ，
        //判断点Q在该线段上的依据是：( Q - P1 ) × ( P2 - P1 ) = 0，且 Q 在以 P1，P2为对角顶点的矩形内
        var pts = polyline.getPath();
        for (var i = 0; i < pts.length - 1; i++) {
            var curPt = pts[i];
            var nextPt = pts[i + 1];
            //首先判断point是否在curPt和nextPt之间，即：此判断该点是否在该线段的外包矩形内
            if (point.lng >= Math.min(curPt.lng, nextPt.lng) && point.lng <= Math.max(curPt.lng, nextPt.lng) &&
                 point.lat >= Math.min(curPt.lat, nextPt.lat) && point.lat <= Math.max(curPt.lat, nextPt.lat)) {
                //判断点是否在直线上公式
                var precision = (curPt.lng - point.lng) * (nextPt.lat - point.lat) - (nextPt.lng - point.lng) * (curPt.lat - point.lat);
                if (precision < 2e-10 && precision > -2e-10) {//实质判断是否接近0
                    return true;
                }
            }
        }
        return false;
    }

    /**
    * 判断点是否多边形内
    * @param {Point} point 点对象
    * @param {Polyline} polygon 多边形对象
    * @returns {Boolean} 点在多边形内返回true,否则返回false
    */
    GeoUtils.isPointInPolygon = function (point, polygon) {
        //检查类型
        if (!(point instanceof BMap.Point) ||
             !(polygon instanceof BMap.Polygon)) {
            return false;
        }

        //首先判断点是否在多边形的外包矩形内，如果在，则进一步判断，否则返回false
        var polygonBounds = polygon.getBounds();
        if (!this.isPointInRect(point, polygonBounds)) {
            return false;
        }

        var pts = polygon.getPath(); //获取多边形点

        //下述代码来源：http://paulbourke.net/geometry/insidepoly/，进行了部分修改
        //基本思想是利用射线法，计算射线与多边形各边的交点，如果是偶数，则点在多边形外，否则
        //在多边形内。还会考虑一些特殊情况，如点在多边形顶点上，点在多边形边上等特殊情况。

        var N = pts.length;
        var boundOrVertex = true; //如果点位于多边形的顶点或边上，也算做点在多边形内，直接返回true
        var intersectCount = 0; //cross points count of x
        var precision = 2e-10; //浮点类型计算时候与0比较时候的容差
        var p1, p2; //neighbour bound vertices
        var p = point; //测试点

        p1 = pts[0]; //left vertex
        for (var i = 1; i <= N; ++i) {//check all rays
            if (p.equals(p1)) {
                return boundOrVertex; //p is an vertex
            }

            p2 = pts[i % N]; //right vertex
            if (p.lat < Math.min(p1.lat, p2.lat) || p.lat > Math.max(p1.lat, p2.lat)) {//ray is outside of our interests
                p1 = p2;
                continue; //next ray left point
            }
            if (p.lat > Math.min(p1.lat, p2.lat) && p.lat < Math.max(p1.lat, p2.lat)) {//ray is crossing over by the algorithm (common part of)
                if (p.lng <= Math.max(p1.lng, p2.lng)) {//x is before of ray
                    if (p1.lat == p2.lat && p.lng >= Math.min(p1.lng, p2.lng)) {//overlies on a horizontal ray
                        return boundOrVertex;
                    }

                    if (p1.lng == p2.lng) {//ray is vertical


                        if (p1.lng == p.lng) {//overlies on a vertical ray
                            return boundOrVertex;
                        } else {//before ray
                            ++intersectCount;
                        }
                    } else {//cross point on the left side


                        var xinters = (p.lat - p1.lat) * (p2.lng - p1.lng) / (p2.lat - p1.lat) + p1.lng; //cross point of lng


                        if (Math.abs(p.lng - xinters) < precision) {//overlies on a ray
                            return boundOrVertex;
                        }

                        if (p.lng < xinters) {//before ray
                            ++intersectCount;
                        }
                    }
                }
            } else {//special case when ray is crossing through the vertex
                if (p.lat == p2.lat && p.lng <= p2.lng) {//p crossing over p2
                    var p3 = pts[(i + 1) % N]; //next vertex


                    if (p.lat >= Math.min(p1.lat, p3.lat) && p.lat <= Math.max(p1.lat, p3.lat)) {//p.lat lies between p1.lat & p3.lat
                        ++intersectCount;
                    } else {
                        intersectCount += 2;
                    }
                }
            }
            p1 = p2; //next ray left point
        }

        if (intersectCount % 2 == 0) {//偶数在多边形外
            return false;
        } else { //奇数在多边形内
            return true;
        }
    }

    /**
    * 将度转化为弧度
    * @param {degree} Number 度
    * @returns {Number} 弧度
    */
    GeoUtils.degreeToRad = function (degree) {
        return Math.PI * degree / 180;
    }

    /**
    * 将弧度转化为度
    * @param {radian} Number 弧度
    * @returns {Number} 度
    */
    GeoUtils.radToDegree = function (rad) {
        return (180 * rad) / Math.PI;
    }

    /**
    * 将v值限定在a,b之间，纬度使用
    */
    function _getRange(v, a, b) {
        if (a != null) {
            v = Math.max(v, a);
        }
        if (b != null) {
            v = Math.min(v, b);
        }
        return v;
    }

    /**
    * 将v值限定在a,b之间，经度使用
    */
    function _getLoop(v, a, b) {
        while (v > b) {
            v -= b - a
        }
        while (v < a) {
            v += b - a
        }
        return v;
    }

    /**
    * 计算两点之间的距离,两点坐标必须为经纬度
    * @param {point1} Point 点对象
    * @param {point2} Point 点对象
    * @returns {Number} 两点之间距离，单位为米
    */
    GeoUtils.getDistance = function (point1, point2) {
        //判断类型
        if (!(point1 instanceof BMap.Point) ||
             !(point2 instanceof BMap.Point)) {
            return 0;
        }

        point1.lng = _getLoop(point1.lng, -180, 180);
        point1.lat = _getRange(point1.lat, -74, 74);
        point2.lng = _getLoop(point2.lng, -180, 180);
        point2.lat = _getRange(point2.lat, -74, 74);

        var x1, x2, y1, y2;
        x1 = GeoUtils.degreeToRad(point1.lng);
        y1 = GeoUtils.degreeToRad(point1.lat);
        x2 = GeoUtils.degreeToRad(point2.lng);
        y2 = GeoUtils.degreeToRad(point2.lat);

        return EARTHRADIUS * Math.acos((Math.sin(y1) * Math.sin(y2) + Math.cos(y1) * Math.cos(y2) * Math.cos(x2 - x1)));
    }

    /**
    * 计算折线或者点数组的长度
    * @param {Polyline|Array} polyline 折线对象或者点数组
    * @returns {Number} 折线或点数组对应的长度
    */
    GeoUtils.getPolylineDistance = function (polyline) {
        //检查类型
        if (polyline instanceof BMap.Polyline ||
             polyline instanceof Array) {
            //将polyline统一为数组
            var pts;
            if (polyline instanceof BMap.Polyline) {
                pts = polyline.getPath();
            } else {
                pts = polyline;
            }

            if (pts.length < 2) {//小于2个点，返回0
                return 0;
            }

            //遍历所有线段将其相加，计算整条线段的长度
            var totalDis = 0;
            for (var i = 0; i < pts.length - 1; i++) {
                var curPt = pts[i];
                var nextPt = pts[i + 1]
                var dis = GeoUtils.getDistance(curPt, nextPt);
                totalDis += dis;
            }

            return totalDis;

        } else {
            return 0;
        }
    }

    /**
    * 计算多边形面或点数组构建图形的面积,注意：坐标类型只能是经纬

    度，且不适合计算自相交多边形的面积
    * @param {Polygon|Array} polygon 多边形面对象或者点数

    组
    * @returns {Number} 多边形面或点数组构成图形的面积
    */
    GeoUtils.getPolygonArea = function (polygon) {
        //检查类型
        if (!(polygon instanceof BMap.Polygon) &&
             !(polygon instanceof Array)) {
            return 0;
        }
        var pts;
        if (polygon instanceof BMap.Polygon) {
            pts = polygon.getPath();
        } else {
            pts = polygon;
        }

        if (pts.length < 3) {//小于3个顶点，不能构建面
            return 0;
        }

        var totalArea = 0; //初始化总面积
        var LowX = 0.0;
        var LowY = 0.0;
        var MiddleX = 0.0;
        var MiddleY = 0.0;
        var HighX = 0.0;
        var HighY = 0.0;
        var AM = 0.0;
        var BM = 0.0;
        var CM = 0.0;
        var AL = 0.0;
        var BL = 0.0;
        var CL = 0.0;
        var AH = 0.0;
        var BH = 0.0;
        var CH = 0.0;
        var CoefficientL = 0.0;
        var CoefficientH = 0.0;
        var ALtangent = 0.0;
        var BLtangent = 0.0;
        var CLtangent = 0.0;
        var AHtangent = 0.0;
        var BHtangent = 0.0;
        var CHtangent = 0.0;
        var ANormalLine = 0.0;
        var BNormalLine = 0.0;
        var CNormalLine = 0.0;
        var OrientationValue = 0.0;
        var AngleCos = 0.0;
        var Sum1 = 0.0;
        var Sum2 = 0.0;
        var Count2 = 0;
        var Count1 = 0;
        var Sum = 0.0;
        var Radius = EARTHRADIUS; //6378137.0,WGS84椭球半径
        var Count = pts.length;
        for (var i = 0; i < Count; i++) {
            if (i == 0) {
                LowX = pts[Count - 1].lng * Math.PI / 180;
                LowY = pts[Count - 1].lat * Math.PI / 180;
                MiddleX = pts[0].lng * Math.PI / 180;
                MiddleY = pts[0].lat * Math.PI / 180;
                HighX = pts[1].lng * Math.PI / 180;
                HighY = pts[1].lat * Math.PI / 180;
            }
            else if (i == Count - 1) {
                LowX = pts[Count - 2].lng * Math.PI / 180;
                LowY = pts[Count - 2].lat * Math.PI / 180;
                MiddleX = pts[Count - 1].lng * Math.PI / 180;
                MiddleY = pts[Count - 1].lat * Math.PI / 180;
                HighX = pts[0].lng * Math.PI / 180;
                HighY = pts[0].lat * Math.PI / 180;
            }
            else {
                LowX = pts[i - 1].lng * Math.PI / 180;
                LowY = pts[i - 1].lat * Math.PI / 180;
                MiddleX = pts[i].lng * Math.PI / 180;
                MiddleY = pts[i].lat * Math.PI / 180;
                HighX = pts[i + 1].lng * Math.PI / 180;
                HighY = pts[i + 1].lat * Math.PI / 180;
            }
            AM = Math.cos(MiddleY) * Math.cos(MiddleX);
            BM = Math.cos(MiddleY) * Math.sin(MiddleX);
            CM = Math.sin(MiddleY);
            AL = Math.cos(LowY) * Math.cos(LowX);
            BL = Math.cos(LowY) * Math.sin(LowX);
            CL = Math.sin(LowY);
            AH = Math.cos(HighY) * Math.cos(HighX);
            BH = Math.cos(HighY) * Math.sin(HighX);
            CH = Math.sin(HighY);
            CoefficientL = (AM * AM + BM * BM + CM * CM) / (AM * AL + BM * BL + CM * CL);
            CoefficientH = (AM * AM + BM * BM + CM * CM) / (AM * AH + BM * BH + CM * CH);
            ALtangent = CoefficientL * AL - AM;
            BLtangent = CoefficientL * BL - BM;
            CLtangent = CoefficientL * CL - CM;
            AHtangent = CoefficientH * AH - AM;
            BHtangent = CoefficientH * BH - BM;
            CHtangent = CoefficientH * CH - CM;
            AngleCos = (AHtangent * ALtangent + BHtangent * BLtangent + CHtangent * CLtangent) / (Math.sqrt(AHtangent * AHtangent + BHtangent * BHtangent + CHtangent * CHtangent) * Math.sqrt(ALtangent * ALtangent + BLtangent * BLtangent + CLtangent * CLtangent));
            AngleCos = Math.acos(AngleCos);
            ANormalLine = BHtangent * CLtangent - CHtangent * BLtangent;
            BNormalLine = 0 - (AHtangent * CLtangent - CHtangent * ALtangent);
            CNormalLine = AHtangent * BLtangent - BHtangent * ALtangent;
            if (AM != 0)
                OrientationValue = ANormalLine / AM;
            else if (BM != 0)
                OrientationValue = BNormalLine / BM;
            else
                OrientationValue = CNormalLine / CM;
            if (OrientationValue > 0) {
                Sum1 += AngleCos;
                Count1++;
            }
            else {
                Sum2 += AngleCos;
                Count2++;
            }
        }
        var tempSum1, tempSum2;
        tempSum1 = Sum1 + (2 * Math.PI * Count2 - Sum2);
        tempSum2 = (2 * Math.PI * Count1 - Sum1) + Sum2;
        if (Sum1 > Sum2) {
            if ((tempSum1 - (Count - 2) * Math.PI) < 1)
                Sum = tempSum1;
            else
                Sum = tempSum2;
        }
        else {
            if ((tempSum2 - (Count - 2) * Math.PI) < 1)
                Sum = tempSum2;
            else
                Sum = tempSum1;
        }
        totalArea = (Sum - (Count - 2) * Math.PI) * Radius * Radius;
        return totalArea; //返回总面积
    }

})(); //闭包结束

注意：

BMapLib.GeoUtils.getPolygonArea(polygon)  不适合计算自相交多边形的面积(封闭的面积)

 

转载于:https://www.cnblogs.com/grimm/p/5097346.html