百度地图API 判断点是否在圆形内

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百度地图API 判断点是否在圆形内

  /*** @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<a href="symbols/BMapLib.GeoUtils.html">GeoUtils</a>，* 基于Baidu Map API 1.2。** @author Baidu Map Api Group * @version 1.2*//** * @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<b>入口</b>。* 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falsevar 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0return 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falsevar 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：/，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truevar 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 verticesvar 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 rayreturn boundOrVertex;}if(p1.lng == p2.lng){//ray is vertical                        if(p1.lng == p.lng){//overlies on a vertical rayreturn 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 rayreturn 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<Point>} 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0return 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<Point>} 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;elseOrientationValue = 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;elseSum = tempSum2;}else {if ((tempSum2 - (Count - 2) * Math.PI) < 1)Sum = tempSum2;elseSum = tempSum1;}totalArea = (Sum - (Count - 2) * Math.PI) * Radius * Radius;return totalArea; //返回总面积}})();//闭包结束

使用方法：

var point = new BMap.Point(x,y)
var circle = new BMap.Circle(mPoint,1000,{fillColor:"blue", strokeWeight: 1 ,fillOpacity: 0.3, strokeOpacity: 0.3});if(BMapLib.GeoUtils.isPointInCircle(point,circle)){alert("该point在circle内");
}

链接：GeoUtils.js
作者：itmyhome

本文标签： 百度地图API 判断点是否在圆形内