点是否在片区内,适用于百度&腾讯地图等
一般的O2O项目,需要使用片区概念,需要划分片区从线上规范化线下。
package com.sun4j.module.util;
import com.daoles.module.entity.Area;
import com.daoles.module.entity.AreaInfo;
import com.daoles.module.service.AreaInfoService;
import com.daoles.module.service.AreaService;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* description: 技术百度地图中的点在某个片区中
* Created by Sunlight on 2017/4/27.
*/
public class MapTools {
/**
* 传入一个坐标点判断
* @param areaService
* @param areaInfoService
* @param x 经度
* @param y 纬度
* @return 返回改点对应的片区
*/
public static Area getAreaByPoint(AreaService areaService, AreaInfoService areaInfoService,Double x,Double y){
Point2D.Double point = new Point2D.Double(x, y);
Map<String,Object> params=new HashMap<>();
params.put("deleted",0);
//查询所有片区
List<Area> areas=areaService.findList(params);
if (areas.size()==0){
return null;
}
for (Area area : areas){
params=new HashMap<>();
params.put("areaId",area.getId());
List<AreaInfo> areaInfos=areaInfoService.findList(params);
if (areaInfos.size()==0){
continue;
}
List<Point2D.Double> pts = new ArrayList<Point2D.Double>();
for (AreaInfo info : areaInfos) {
pts.add(new Point2D.Double(info.getLng(), info.getLat()));
}
if (IsPtInPoly(point, pts)) {
System.out.println("===========点在多边形内===========");
return area;
} else {
System.out.println("===========点在多边形外===========");
continue;
}
}
return null;
}
/**
* 判断点是否在多边形内
*
* @param point 检测点
* @param pts 多边形的顶点
* @return 点在多边形内返回true, 否则返回false
*/
public static boolean IsPtInPoly(Point2D.Double point, List<Point2D.Double> pts) {
int N = pts.size();
boolean 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
int intersectCount = 0;//cross points count of x
double precision = 2e-10; //浮点类型计算时候与0比较时候的容差
Point2D.Double p1, p2;//neighbour bound vertices
Point2D.Double p = point; //当前点
p1 = pts.get(0);//left vertex
for (int i = 1; i <= N; ++i) {//check all rays
if (p.equals(p1)) {
return boundOrVertex;//p is an vertex
}
p2 = pts.get(i % N);//right vertex
if (p.x < Math.min(p1.x, p2.x) || p.x > Math.max(p1.x, p2.x)) {//ray is outside of our interests
p1 = p2;
continue;//next ray left point
}
if (p.x > Math.min(p1.x, p2.x) && p.x < Math.max(p1.x, p2.x)) {//ray is crossing over by the algorithm (common part of)
if (p.y <= Math.max(p1.y, p2.y)) {//x is before of ray
if (p1.x == p2.x && p.y >= Math.min(p1.y, p2.y)) {//overlies on a horizontal ray
return boundOrVertex;
}
if (p1.y == p2.y) {//ray is vertical
if (p1.y == p.y) {//overlies on a vertical ray
return boundOrVertex;
} else {//before ray
++intersectCount;
}
} else {//cross point on the left side
double xinters = (p.x - p1.x) * (p2.y - p1.y) / (p2.x - p1.x) + p1.y;//cross point of y
if (Math.abs(p.y - xinters) < precision) {//overlies on a ray
return boundOrVertex;
}
if (p.y < xinters) {//before ray
++intersectCount;
}
}
}
} else {//special case when ray is crossing through the vertex
if (p.x == p2.x && p.y <= p2.y) {//p crossing over p2
Point2D.Double p3 = pts.get((i + 1) % N); //next vertex
if (p.x >= Math.min(p1.x, p3.x) && p.x <= Math.max(p1.x, p3.x)) {//p.x lies between p1.x & p3.x
++intersectCount;
} else {
intersectCount += 2;
}
}
}
p1 = p2;//next ray left point
}
return intersectCount % 2 != 0;
}
}