圆

double x,double y,double radius(米)

double r = radius/(2*Math.PI*6371000)*360;半径转经纬度

double angle = 0;

double p_x = 0;

double p_y = 0;

double angleSpan = 10;每隔多少度，加个点

int count = (int)(360/angleSpan+1);点数，+1保证尾点起点重合

List<Point> pointList = new ArrayList();

for(int i=0;i<count;i++){

p_x = x+r*Math.sin(angle*Math.PI/180);

p_y = y+r*Math.cos(angle*Math.PI/180);

angle +=angleSpan;

point = new Point(p_x,P_y);

pointList.add(point);

}

return pointList;