判断一个点是否在某个多边形范围内(Java和python实现)

男娘i 2024-04-19 14:30 84阅读 0赞

## 一.java实现 ##

**所用jar包:**

<dependency>
    			<groupId>nl.cloudfarming.client</groupId>
    			<artifactId>lib-geotools</artifactId>
    			<version>2.7.5</version>
    		</dependency>
    		<dependency>
    			<groupId>com.vividsolutions</groupId>
    			<artifactId>jts</artifactId>
    			<version>1.13</version>
    		</dependency>

### 1.传入点或多边形的wkt字符串 ###

/**
         * 判断点是否在某个多边形上
         * @param pointWkt
         * @param ploygonWkt
         * @param isContainsEdge 是否包含边界,如果为true,那么在边界上时也算在多边形内
         * @return
         */
        public static boolean judgePointIfInRegion(String pointWkt, String ploygonWkt,
                                                   boolean isContainsEdge) {
    
            WKTReader reader = new WKTReader(JTSFactoryFinder.getGeometryFactory(null));
            Geometry point = null;
            Geometry poly = null;
            try {
                point = reader.read(pointWkt);
                poly = reader.read(ploygonWkt);
            } catch (Exception e) {
                e.printStackTrace();
            }
    
            if(!isContainsEdge){
                // 判断是否在区域内
                return poly.contains(point);
            }else{
                // 判断是否相交或在区域内
                return poly.intersects(point) || poly.contains(point);
            }
        }

**测试:**

public static void main(String[] args) {
    
            String wktPoly = "POLYGON ((116.37150802 39.76183098000003,116.38340802 39.76183098000003,116.38340802 39.7579994886348,116.3798506328265 39.75717762188538,116.3780662872948 39.75685062893655,116.3769283831572 39.75675043493624,116.376230979047 39.75674108396044,116.3755731966328 39.75678290806371,116.3742240792109 39.75690322058387,116.3735865028596 39.75704296592238,116.3731405117154 39.75722575706936,116.372299771974 39.75765971936517,116.3718584872889 39.75793849075126,116.3715491604592 39.75817657788684,116.37150802 39.75821656329189,116.37150802 39.76183098000003))"; //请自行搜素了解wkt格式
            String wktPoint = "POINT (116.37150802 39.76183098000003)";
    
            System.out.println(judgePointIfInRegion(wktPoint,wktPoly,true));
    
    
        }

**输出:**

true

### 2.传入点或多边形的坐标列表 ###

/**
         * 判断点是否在某个多边形上
         * @param pointCoord
         * @param ploygonCoords
         * @param isContainsEdge 是否包含边界,如果为true,那么在边界上时也算在多边形内
         * @return
         */
        public static boolean judgePointIfInRegion(List<Double> pointCoord,
                                                   List<List<List<Double>>> ploygonCoords,boolean isContainsEdge) {
    
            String pointWkt = "POINT " + pointCoord.toString().
                    replace("[","(").replace("]",")").
                    replace(","," ");
    
            String ploygonWkt = "POLYGON " + ploygonCoords.toString().replace(" ", "").
                    replace("]],[[", ");(").replace("],[", ";").
                    replace("[[[", "((").replace("]]]", "))").
                    replace(",", " ").replace(";", ",");
    
            WKTReader reader = new WKTReader(JTSFactoryFinder.getGeometryFactory(null));
            Geometry point = null;
            Geometry poly = null;
            try {
                point = reader.read(pointWkt);
                poly = reader.read(ploygonWkt);
            } catch (Exception e) {
                e.printStackTrace();
            }
    
            if(!isContainsEdge){
                // 判断是否在区域内
                return poly.contains(point);
            }else{
                // 判断是否相交或在区域内
                return poly.intersects(point) || poly.contains(point);
            }
            
        }

**测试:**

public static void main(String[] args) {
    
            Gson gson = new Gson();
            String pointCoordStr = "[113.775698, 30.236892]";
            List pointCoord = gson.fromJson(pointCoordStr,List.class);
    
            String ploygonCoordsStr = "[[[113.76708006000003,30.231097985000019],[113.77808006000006,30.231097985000019],[113.77808006000006,30.240197984999959]," +
                    "[113.76708006000003,30.240197984999959],[113.76708006000003,30.231097985000019]]]";
            List ploygonCoords = gson.fromJson(ploygonCoordsStr,List.class);
    
            System.out.println(judgePointIfInRegion(pointCoord,ploygonCoords,true));
        }

**输出:**

true

## 二.Python实现 ##

**射线法实现**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3h5eTEwMjg_size_16_color_FFFFFF_t_70][]

###  法一: ###

'''
    判断某个坐标是否在某个封闭区域内
    
    '''
    
    
    # 判断该点是否在该条线上
    
    # point:点坐标,如:[113.775698, 30.236892]
    # o : 该条线的起点
    # d : 该条线的终点
    def is_in_line(point, o, d):
        # 先判断该点是否在线段范围内,如果不在,
        # 则就算在该方程的直线上但也不在该线段上
        if o[1] > point[1] and d[1] > point[1]:  # 该点纵坐标小于线段最小纵坐标
            return False
        if o[1] < point[1] and d[1] < point[1]:  # 该点纵坐标大于线段最大纵坐标
            return False
        if o[0] > point[0] and d[0] > point[0]:  # 该点横坐标小于线段最小横坐标
            return False
        if o[0] < point[0] and d[0] < point[0]:  # 该点横坐标大于线段最大横坐标
            return False
    
        # 若线段为垂直直线,则该点的横坐标等于该线段的横坐标才说明在该线段上
        if o[0] == d[0]:
            return True if point[0] == o[0] else False
    
        # 通过输入的两个点计算一元一次方程,通过输入x,计算y
        a = (d[1] - o[1]) / (d[0] - o[0])
        b = (d[0] * o[1] - o[0] * d[1]) / (d[0] - o[0])
        y = a * point[0] + b
        return True if y == point[1] else False
    
    
    # 假设以该点向右水平做射线,判断该点是否与该线段有交点(只要线段与射线相交则为true)
    # point:点坐标,如:[113.775698, 30.236892]
    # o : 该条线的起点
    # d : 该条线的终点
    def is_ray_intersects_segment(point, o, d):
        if o[1] == d[1]:  # 如果线段是水平直线,则直接无交点
            return False
        # 先判断该点是否在线段范围内,如果不在,
        # 则就算在该方程的直线上但也不在该线段上
        if o[1] > point[1] and d[1] > point[1]:  # 该点纵坐标小于等于线段最小纵坐标
            return False
        if o[1] < point[1] and d[1] < point[1]:  # 该点纵坐标大于等于线段最大纵坐标
            return False
    
        # 先求出一元一次方程求交点
        # 若线段为垂直直线,则该点的横坐标应该小于该点的横坐标才能有交点
        # if o[0] == d[0]:
        #     return True if point[0] < o[0] else False
        #
        # # 通过输入的两个点计算一元一次方程,通过输入x,计算y
        # a = (d[1] - o[1]) / (d[0] - o[0])
        # b = (d[0] * o[1] - o[0] * d[1]) / (d[0] - o[0])
        # x = (point[1] - b) / a
    
        # 利用三角形比例关系求交点
        x = d[0] - (d[0] - o[0]) * (d[1] - point[1]) / (d[1] - o[1])
    
        # 如果该点的横坐标小于相同水平线上交点的横坐标,则有交点
        return True if point[0] < x else False
    
    
    """
    判断是否在矩形区域内
    
    point_coord:点坐标,如:[113.775698, 30.236892]
    polygon_coords:封闭多边形,如:[[[113.76708006000003,30.231097985000019],
    [113.77808006000006,30.231097985000019],[113.76708006000003,30.231097985000019]]]
    is_contains_edge: 是否包含边界,如果为true,那么在边界上时也算在多边形内
    """
    
    
    def is_point_in_polygon(point_coord, polygon_coords, is_contains_edge):
        intersect_count = 0  # 交点个数
        for polygon in polygon_coords:
            # 循环每条边
            for i in range(len(polygon) - 1):
                origin_point = polygon[i]
                destination_point = polygon[i + 1]
    
                # 是否包含存在直线上的点
                if is_in_line(point_coord, origin_point, destination_point):
                    return True if is_contains_edge else False
    
                if is_ray_intersects_segment(point_coord, origin_point, destination_point):
                    # 有交点就加1
                    intersect_count += 1
    
        # 如果恰好与端点相交,则查看相应的端点,并减去与该点相同纵坐标且在该点右侧的点的个数
        endpoint_intersects_count = 0
        for polygon in polygon_coords:
            # 遍历每一个点,但是因为最后一个点和第一个点是重复的,所以最后一个不遍历
            for i in polygon[:-1]:
                if i[1] == point_coord[1] and i[0] > point_coord[0]:
                    endpoint_intersects_count += 1
        intersect_count -= endpoint_intersects_count
        return True if intersect_count % 2 == 1 else False
    
    
    poly = [[
        [2.0, 4.0],
        [2.0, 6.0],
        [4.0, 8.0],
        [6.0, 8.0],
        [8.0, 6.0],
        [8.0, 4.0],
        [6.0, 2.0],
        [4.0, 2.0],
        [2.0, 4.0]
    ],
        [
            [3.0, 5.0],
            [4.0, 7.0],
            [6.0, 7.0],
            [7.0, 6.0],
            [6.0, 5.0],
            [3.0, 5.0]
        ]
    ]
    
    poi = [6.5, 7]
    
    print(is_point_in_polygon(poi, poly, False))

###  法二: ###

'''
    判断某个坐标是否在某个封闭区域内
    
    '''
    
    
    # 判断该点是否在该条线上
    
    # point:点坐标,如:[113.775698, 30.236892]
    # o : 该条线的起点
    # d : 该条线的终点
    def is_in_line(point, o, d):
        # 先判断该点是否在线段范围内,如果不在,
        # 则就算在该方程的直线上但也不在该线段上
        if o[1] > point[1] and d[1] > point[1]:  # 该点纵坐标小于线段最小纵坐标
            return False
        if o[1] < point[1] and d[1] < point[1]:  # 该点纵坐标大于线段最大纵坐标
            return False
        if o[0] > point[0] and d[0] > point[0]:  # 该点横坐标小于线段最小横坐标
            return False
        if o[0] < point[0] and d[0] < point[0]:  # 该点横坐标大于线段最大横坐标
            return False
    
        # 若线段为垂直直线,则该点的横坐标等于该线段的横坐标才说明在该线段上
        if o[0] == d[0]:
            return True if point[0] == o[0] else False
    
        # 通过输入的两个点计算一元一次方程,通过输入x,计算y
        a = (d[1] - o[1]) / (d[0] - o[0])
        b = (d[0] * o[1] - o[0] * d[1]) / (d[0] - o[0])
        y = a * point[0] + b
        return True if y == point[1] else False
    
    
    # 假设以该点向右水平做射线,判断该点是否与该线段有交点(当射线与线段下端点相交时为False)
    # point:点坐标,如:[113.775698, 30.236892]
    # o : 该条线的起点
    # d : 该条线的终点
    def is_ray_intersects_segment(point, o, d):
        if o[1] == d[1]:  # 如果线段是水平直线,则直接无交点
            return False
        # 先判断该点是否在线段范围内,如果不在,
        # 则就算在该方程的直线上但也不在该线段上
        if o[1] > point[1] and d[1] > point[1]:  # 该点纵坐标小于等于线段最小纵坐标
            return False
        if o[1] < point[1] and d[1] < point[1]:  # 该点纵坐标大于等于线段最大纵坐标
            return False
        if o[1] == point[1] and d[1] > point[1]:  # 若o点为下端点且交点为下端点时
            return False
        if d[1] == point[1] and o[1] > point[1]:  # 交d点为下端点且交点为下端点时
            return False
    
        # 注释部分为 先求出一元一次方程求交点
        # 若线段为垂直直线,则该点的横坐标应该小于该点的横坐标才能有交点
        # if o[0] == d[0]:
        #     return True if point[0] < o[0] else False
        #
        # # 通过输入的两个点计算一元一次方程,通过输入x,计算y
        # a = (d[1] - o[1]) / (d[0] - o[0])
        # b = (d[0] * o[1] - o[0] * d[1]) / (d[0] - o[0])
        # x = (point[1] - b) / a
    
        # 利用三角形比例关系求交点
        x = d[0] - (d[0] - o[0]) * (d[1] - point[1]) / (d[1] - o[1])
        # 如果该点的横坐标小于相同水平线上交点的横坐标,则有交点
        return True if point[0] < x else False
    
    
    """
    判断是否在矩形区域内
    
    point_coord:点坐标,如:[113.775698, 30.236892]
    polygon_coords:封闭多边形,如:[[[113.76708006000003,30.231097985000019],
    [113.77808006000006,30.231097985000019],[113.76708006000003,30.231097985000019]]]
    is_contains_edge: 是否包含边界,如果为true,那么在边界上时也算在多边形内
    """
    
    
    def is_point_in_polygon(point_coord, polygon_coords, is_contains_edge):
        intersect_count = 0  # 交点个数
        for polygon in polygon_coords:
            # 循环每条边
            for i in range(len(polygon) - 1):
                origin_point = polygon[i]
                destination_point = polygon[i + 1]
    
                # 是否包含存在直线上的点
                if is_in_line(point_coord, origin_point, destination_point):
                    return True if is_contains_edge else False
    
                if is_ray_intersects_segment(point_coord, origin_point, destination_point):
                    # 有交点就加1
                    intersect_count += 1
        return True if intersect_count % 2 == 1 else False
    
    
    poly = [[
        [2.0, 4.0],
        [2.0, 6.0],
        [4.0, 8.0],
        [6.0, 8.0],
        [8.0, 6.0],
        [8.0, 4.0],
        [6.0, 2.0],
        [4.0, 2.0],
        [2.0, 4.0]
    ],
        [
            [3.0, 5.0],
            [4.0, 7.0],
            [6.0, 7.0],
            [7.0, 6.0],
            [6.0, 5.0],
            [3.0, 5.0]
        ]
    ]
    
    poi = [5, 5]
    
    print(is_point_in_polygon(poi, poly, False))

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3h5eTEwMjg_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/f848c79269484e5aa1f64234e52a2966.png