505 lines
17 KiB
JavaScript
505 lines
17 KiB
JavaScript
/**
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* @fileoverview GeoUtils类提供若干几何算法，用来帮助用户判断点与矩形、
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* 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。
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* 主入口类是<a href="symbols/BMapLib.GeoUtils.html">GeoUtils</a>，
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* 基于Baidu Map API 1.2。
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*
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* @author Baidu Map Api Group
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* @version 1.2
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*/
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//BMapLib.GeoUtils.degreeToRad(Number)
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//将度转化为弧度
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//BMapLib.GeoUtils.getDistance(Point, Point)
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//计算两点之间的距离,两点坐标必须为经纬度
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//BMapLib.GeoUtils.getPolygonArea(polygon)
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//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)
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//BMapLib.GeoUtils.getPolylineDistance(polyline)
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//计算折线或者点数组的长度
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//BMapLib.GeoUtils.isPointInCircle(point, circle)
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//判断点是否在圆形内
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//BMapLib.GeoUtils.isPointInPolygon(point, polygon)
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//判断点是否多边形内
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//BMapLib.GeoUtils.isPointInRect(point, bounds)
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//判断点是否在矩形内
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//BMapLib.GeoUtils.isPointOnPolyline(point, polyline)
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//判断点是否在折线上
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//BMapLib.GeoUtils.radToDegree(Number)
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//将弧度转化为度
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function getCenterPoint(path)
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{
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//var path = e.;//Array<Point> 返回多边型的点数组
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//var ret=parseFloat(num1)+parseFloat(num2);
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var x = 0.0;
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var y = 0.0;
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for(var i=0;i<path.length;i++){
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x=x+ parseFloat(path[i].lng);
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y=y+ parseFloat(path[i].lat);
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}
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x=x/path.length;
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y=y/path.length;
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return new BMap.Point(x,y);
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}
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/**
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* @namespace BMap的所有library类均放在BMapLib命名空间下
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*/
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var BMapLib = {};
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(function () {
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/**
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* 地球半径
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*/
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var EARTHRADIUS = 6370996.81;
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/**
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* @exports GeoUtils as BMapLib.GeoUtils
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*/
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var GeoUtils =
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/**
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* GeoUtils类，静态类，勿需实例化即可使用
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* @class GeoUtils类的<b>入口</b>。
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* 该类提供的都是静态方法，勿需实例化即可使用。
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*/
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BMapLib.GeoUtils = function () {
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}
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/**
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* 判断点是否在矩形内
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* @param {Point} point 点对象
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* @param {Bounds} bounds 矩形边界对象
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* @returns {Boolean} 点在矩形内返回true,否则返回false
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*/
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GeoUtils.isPointInRect = function (point, bounds) {
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//检查类型是否正确
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if (!(point instanceof BMap.Point) ||
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!(bounds instanceof BMap.Bounds)) {
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return false;
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}
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var sw = bounds.getSouthWest(); //西南脚点
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var ne = bounds.getNorthEast(); //东北脚点
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return (point.lng >= sw.lng && point.lng <= ne.lng && point.lat >= sw.lat && point.lat <= ne.lat);
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}
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/**
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* 判断点是否在圆形内
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* @param {Point} point 点对象
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* @param {Circle} circle 圆形对象
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* @returns {Boolean} 点在圆形内返回true,否则返回false
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*/
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GeoUtils.isPointInCircle = function (point, circle) {
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//检查类型是否正确
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if (!(point instanceof BMap.Point) ||
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!(circle instanceof BMap.Circle)) {
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return false;
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}
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//point与圆心距离小于圆形半径，则点在圆内，否则在圆外
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var c = circle.getCenter();
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var r = circle.getRadius();
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var dis = GeoUtils.getDistance(point, c);
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if (dis <= r) {
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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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/**
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* 判断点是否在折线上
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* @param {Point} point 点对象
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* @param {Polyline} polyline 折线对象
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* @returns {Boolean} 点在折线上返回true,否则返回false
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*/
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GeoUtils.isPointOnPolyline = function (point, polyline) {
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//检查类型
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if (!(point instanceof BMap.Point) ||
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!(polyline instanceof BMap.Polyline)) {
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return false;
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}
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//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
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var lineBounds = polyline.getBounds();
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if (!this.isPointInRect(point, lineBounds)) {
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return false;
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}
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//判断点是否在线段上，设点为Q，线段为P1P2 ，
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//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
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var pts = polyline.getPath();
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for (var i = 0; i < pts.length - 1; i++) {
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var curPt = pts[i];
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var nextPt = pts[i + 1];
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//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
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if (point.lng >= Math.min(curPt.lng, nextPt.lng) && point.lng <= Math.max(curPt.lng, nextPt.lng) &&
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point.lat >= Math.min(curPt.lat, nextPt.lat) && point.lat <= Math.max(curPt.lat, nextPt.lat)) {
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//判断点是否在直线上公式
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var precision = (curPt.lng - point.lng) * (nextPt.lat - point.lat) - (nextPt.lng - point.lng) * (curPt.lat - point.lat);
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if (precision < 2e-10 && precision > -2e-10) {//实质判断是否接近0
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return true;
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}
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}
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}
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return false;
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}
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/**
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* 判断点是否多边形内
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* @param {Point} point 点对象
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* @param {Polyline} polygon 多边形对象
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* @returns {Boolean} 点在多边形内返回true,否则返回false
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*/
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GeoUtils.isPointInPolygon = function (point, polygon) {
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//检查类型
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if (!(point instanceof BMap.Point) ||
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!(polygon instanceof BMap.Polygon)) {
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return false;
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}
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//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
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var polygonBounds = polygon.getBounds();
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if (!this.isPointInRect(point, polygonBounds)) {
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return false;
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}
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var pts = polygon.getPath(); //获取多边形点
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//下述代码来源：http://paulbourke.net/geometry/insidepoly/，进行了部分修改
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//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
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//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。
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var N = pts.length;
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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
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var intersectCount = 0; //cross points count of x
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var precision = 2e-10; //浮点类型计算时候与0比较时候的容差
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var p1, p2; //neighbour bound vertices
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var p = point; //测试点
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p1 = pts[0]; //left vertex
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for (var i = 1; i <= N; ++i) {//check all rays
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if (p.equals(p1)) {
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return boundOrVertex; //p is an vertex
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}
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p2 = pts[i % N]; //right vertex
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if (p.lat < Math.min(p1.lat, p2.lat) || p.lat > Math.max(p1.lat, p2.lat)) {//ray is outside of our interests
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p1 = p2;
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continue; //next ray left point
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}
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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)
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if (p.lng <= Math.max(p1.lng, p2.lng)) {//x is before of ray
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if (p1.lat == p2.lat && p.lng >= Math.min(p1.lng, p2.lng)) {//overlies on a horizontal ray
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return boundOrVertex;
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}
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if (p1.lng == p2.lng) {//ray is vertical
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if (p1.lng == p.lng) {//overlies on a vertical ray
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return boundOrVertex;
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} else {//before ray
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++intersectCount;
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}
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} else {//cross point on the left side
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var xinters = (p.lat - p1.lat) * (p2.lng - p1.lng) / (p2.lat - p1.lat) + p1.lng; //cross point of lng
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if (Math.abs(p.lng - xinters) < precision) {//overlies on a ray
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return boundOrVertex;
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}
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if (p.lng < xinters) {//before ray
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++intersectCount;
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}
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}
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}
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} else {//special case when ray is crossing through the vertex
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if (p.lat == p2.lat && p.lng <= p2.lng) {//p crossing over p2
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var p3 = pts[(i + 1) % N]; //next vertex
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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
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++intersectCount;
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} else {
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intersectCount += 2;
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}
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}
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}
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p1 = p2; //next ray left point
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}
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if (intersectCount % 2 == 0) {//偶数在多边形外
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return false;
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} else { //奇数在多边形内
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return true;
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}
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}
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/**
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* 将度转化为弧度
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* @param {degree} Number 度
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* @returns {Number} 弧度
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*/
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GeoUtils.degreeToRad = function (degree) {
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return Math.PI * degree / 180;
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}
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/**
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* 将弧度转化为度
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* @param {radian} Number 弧度
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* @returns {Number} 度
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*/
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GeoUtils.radToDegree = function (rad) {
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return (180 * rad) / Math.PI;
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}
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/**
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* 将v值限定在a,b之间，纬度使用
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*/
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function _getRange(v, a, b) {
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if (a != null) {
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v = Math.max(v, a);
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}
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if (b != null) {
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v = Math.min(v, b);
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}
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return v;
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}
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/**
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* 将v值限定在a,b之间，经度使用
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*/
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function _getLoop(v, a, b) {
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while (v > b) {
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v -= b - a
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}
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while (v < a) {
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v += b - a
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}
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return v;
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}
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/**
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* 计算两点之间的距离,两点坐标必须为经纬度
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* @param {point1} Point 点对象
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* @param {point2} Point 点对象
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* @returns {Number} 两点之间距离，单位为米
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*/
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GeoUtils.getDistance = function (point1, point2) {
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//判断类型
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// debugger;
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// if (!(point1 instanceof BMap.Point) ||
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// !(point2 instanceof BMap.Point)) {
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// return 0;
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// }
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point1.lng = _getLoop(point1.lng, -180, 180);
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point1.lat = _getRange(point1.lat, -74, 74);
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point2.lng = _getLoop(point2.lng, -180, 180);
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point2.lat = _getRange(point2.lat, -74, 74);
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var x1, x2, y1, y2;
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x1 = GeoUtils.degreeToRad(point1.lng);
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y1 = GeoUtils.degreeToRad(point1.lat);
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x2 = GeoUtils.degreeToRad(point2.lng);
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y2 = GeoUtils.degreeToRad(point2.lat);
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return EARTHRADIUS * Math.acos((Math.sin(y1) * Math.sin(y2) + Math.cos(y1) * Math.cos(y2) * Math.cos(x2 - x1)));
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}
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/**
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* 计算折线或者点数组的长度
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* @param {Polyline|Array<Point>} polyline 折线对象或者点数组
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* @returns {Number} 折线或点数组对应的长度
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*/
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GeoUtils.getPolylineDistance = function (polyline) {
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//检查类型
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if (polyline instanceof BMap.Polyline ||
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polyline instanceof Array) {
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//将polyline统一为数组
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var pts;
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if (polyline instanceof BMap.Polyline) {
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pts = polyline.getPath();
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} else {
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pts = polyline;
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}
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if (pts.length < 2) {//小于2个点，返回0
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return 0;
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}
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//遍历所有线段将其相加，计算整条线段的长度
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var totalDis = 0;
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for (var i = 0; i < pts.length - 1; i++) {
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var curPt = pts[i];
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var nextPt = pts[i + 1]
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var dis = GeoUtils.getDistance(curPt, nextPt);
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totalDis += dis;
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}
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return totalDis;
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} else {
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return 0;
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}
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}
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/**
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* 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
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度，且不适合计算自相交多边形的面积
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* @param {Polygon|Array<Point>} polygon 多边形面对象或者点数
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组
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* @returns {Number} 多边形面或点数组构成图形的面积
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*/
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GeoUtils.getPolygonArea = function (polygon) {
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//检查类型
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if (!(polygon instanceof BMap.Polygon) &&
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!(polygon instanceof Array)) {
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return 0;
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}
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var pts;
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if (polygon instanceof BMap.Polygon) {
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pts = polygon.getPath();
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} else {
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pts = polygon;
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}
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if (pts.length < 3) {//小于3个顶点，不能构建面
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return 0;
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}
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var totalArea = 0; //初始化总面积
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var LowX = 0.0;
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var LowY = 0.0;
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var MiddleX = 0.0;
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var MiddleY = 0.0;
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var HighX = 0.0;
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var HighY = 0.0;
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var AM = 0.0;
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var BM = 0.0;
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var CM = 0.0;
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var AL = 0.0;
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var BL = 0.0;
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var CL = 0.0;
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var AH = 0.0;
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var BH = 0.0;
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var CH = 0.0;
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var CoefficientL = 0.0;
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var CoefficientH = 0.0;
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var ALtangent = 0.0;
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var BLtangent = 0.0;
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var CLtangent = 0.0;
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var AHtangent = 0.0;
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var BHtangent = 0.0;
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var CHtangent = 0.0;
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var ANormalLine = 0.0;
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var BNormalLine = 0.0;
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var CNormalLine = 0.0;
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var OrientationValue = 0.0;
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var AngleCos = 0.0;
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var Sum1 = 0.0;
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var Sum2 = 0.0;
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var Count2 = 0;
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var Count1 = 0;
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var Sum = 0.0;
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var Radius = EARTHRADIUS; //6378137.0,WGS84椭球半径
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var Count = pts.length;
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for (var i = 0; i < Count; i++) {
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if (i == 0) {
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LowX = pts[Count - 1].lng * Math.PI / 180;
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LowY = pts[Count - 1].lat * Math.PI / 180;
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MiddleX = pts[0].lng * Math.PI / 180;
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MiddleY = pts[0].lat * Math.PI / 180;
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HighX = pts[1].lng * Math.PI / 180;
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HighY = pts[1].lat * Math.PI / 180;
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}
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else if (i == Count - 1) {
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LowX = pts[Count - 2].lng * Math.PI / 180;
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LowY = pts[Count - 2].lat * Math.PI / 180;
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MiddleX = pts[Count - 1].lng * Math.PI / 180;
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MiddleY = pts[Count - 1].lat * Math.PI / 180;
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HighX = pts[0].lng * Math.PI / 180;
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HighY = pts[0].lat * Math.PI / 180;
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}
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else {
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LowX = pts[i - 1].lng * Math.PI / 180;
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LowY = pts[i - 1].lat * Math.PI / 180;
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MiddleX = pts[i].lng * Math.PI / 180;
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MiddleY = pts[i].lat * Math.PI / 180;
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HighX = pts[i + 1].lng * Math.PI / 180;
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HighY = pts[i + 1].lat * Math.PI / 180;
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}
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AM = Math.cos(MiddleY) * Math.cos(MiddleX);
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BM = Math.cos(MiddleY) * Math.sin(MiddleX);
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CM = Math.sin(MiddleY);
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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
|
||
|
||
export default BMapLib |