mysql中判断一个点是否在多边形中

1.创建表

CREATE TABLE `c_zone` ( 
  `id` int(11) NOT NULL auto_increment,
  `name` varchar(100) NOT NULL,
  `ploygongeo` text NOT NULL, 
  PRIMARY KEY  (`id`) 
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

 

2.插入数据

INSERT INTO c_zone (name, ploygongeo) VALUES('北京地铁2号线', 'POLYGON((116.362012 39.948906,116.377535 39.954879,116.439914 39.955654,116.442213 39.911947,116.431577 39.911061,116.42669 39.907851,116.363306 39.905859,116.362012 39.948906))'); 

 

INSERT INTO c_zone (name, ploygongeo) VALUES('北京地铁10号线', 'POLYGON((116.29561 39.972465,116.292591 39.976391,116.296185 39.980095,116.30064 39.980482,116.307539 39.980648,116.312785 39.981699,116.324356 39.981975,116.444154 39.983191,116.463557 39.971802,116.46521 39.968429,116.463629 39.966493,116.462551 39.962511,116.467222 39.959249,116.469019 39.955045,116.466216 39.871589,116.460251 39.857799,116.454286 39.851374,116.312785 39.851374,116.309048 39.897666,116.317097 39.904309,116.316163 39.92069,116.30409 39.929765,116.301359 39.93917,116.300568 39.964834,116.29561 39.972465))');

 

3.创建函数

DELIMITER //  
 
CREATE FUNCTION myWithin(p POINT, poly POLYGON) RETURNS INT(1) DETERMINISTIC  
BEGIN  
DECLARE n INT DEFAULT 0;  
DECLARE pX DECIMAL(9,6);  
DECLARE pY DECIMAL(9,6);  
DECLARE ls LINESTRING;  
DECLARE poly1 POINT;  
DECLARE poly1X DECIMAL(9,6);  
DECLARE poly1Y DECIMAL(9,6);  
DECLARE poly2 POINT;  
DECLARE poly2X DECIMAL(9,6);  
DECLARE poly2Y DECIMAL(9,6);  
DECLARE i INT DEFAULT 0;  
DECLARE result INT(1) DEFAULT 0;  
SET pX = X(p);  
SET pY = Y(p);  
SET ls = ExteriorRing(poly);  
SET poly2 = EndPoint(ls);  
SET poly2X = X(poly2);  
SET poly2Y = Y(poly2);  
SET n = NumPoints(ls);  
WHILE i<n DO  
SET poly1 = PointN(ls, (i+1));  
SET poly1X = X(poly1);  
SET poly1Y = Y(poly1);  
IF ( ( ( ( poly1X <= pX ) && ( pX < poly2X ) ) || ( ( poly2X <= pX ) && ( pX < poly1X ) ) ) && ( pY > ( poly2Y - poly1Y ) * ( pX - poly1X ) / ( poly2X - poly1X ) + poly1Y ) ) THEN  
SET result = !result;  
END IF;  
SET poly2X = poly1X;  
SET poly2Y = poly1Y;  
SET i = i + 1;  
END WHILE;  
RETURN result;  
End;  
// 
DELIMITER ;

 

4.查询

SELECT name, substring(ploygongeo,10,length(ploygongeo)-11) from c_zone  
where myWithin(PolygonFromText('Point(116.43747 39.916927)'),PolygonFromText(ploygongeo))>0;