最近在帮一个朋友在GoogleMap上画扇形，GoogleMap本身不提供这种画法，所以需要自己去实现，无赖原来学过的数学也忘记的差不多了，只能求助网络。
国外有一个高手写了一个扩展，地址是：http://econym.org.uk/gmap/eshapes.htm
但里面没有扇形的画法，在此基础上自己增加了扇形的画法：
GPolyline扩展方法：
1 GPolyline.Sector = function(point, radius, sDegree, eDegree, colour, weight, opacity,opts) {
2 var points = [];
3 var step = ((eDegree - sDegree) / 10) || 10;
4
5 points.push(point);
6 for(var i=sDegree;i<eDegree + 0.001;i+=step){
7 points.push(EOffsetBearing(point,radius,i));
8 }
9 points.push(point);
10
11 return new GPolyline(points, colour, weight, opacity, opts);
12 }
GPolygon扩展方法：
1 GPolygon.Sector = function(point, radius, sDegree, eDegree, strokeColour, strokeWeight,Strokepacity, fillColour, fillOpacity, opts) {
2 var points = [];
3 var step = ((eDegree - sDegree) / 10) || 10;
4
5 points.push(point);
6 for(var i=sDegree;i<eDegree + 0.001;i+=step){
7 points.push(EOffsetBearing(point,radius,i));
8 }
9 points.push(point);
10
11 return new GPolygon(points, strokeColour, strokeWeight,Strokepacity, fillColour, fillOpacity, opts);
12 }
使用方法见Demo，下载地址是：https://files.cnblogs.com/liongis/eshapes.rar