STV_Intersect 标量函数
将一个点或多个点与一组多边形在空间上相交。STV_Intersect 标量函数将返回与相交多边形关联的标识符。
行为类型
不可变语法
STV_Intersect( { g | x , y }
USING PARAMETERS index= 'index_name')
参数
g- 包含点的几何或地理 (WGS84) 列。*g *列只能包含点几何图形或地理图形。如果该列包含其他几何或地理类型，STV_Intersect 将会终止并提示错误。
x- X 坐标或经度，FLOAT。
y- y 坐标或纬度，FLOAT。
参数
index = 'index_name'- 空间索引的名称，类型为 VARCHAR。
返回
匹配多边形的标识符。如果点没有与索引中的任何多边形相交，则 STV_Intersect 标量函数将返回 NULL。
示例
以下示例显示了如何使用 STV_Intersect 标量。
使用两个浮点数，返回匹配多边形的 gid 或 NULL：
=> CREATE TABLE pols (gid INT, geom GEOMETRY(1000));
CREATE TABLE
=> COPY pols(gid, gx filler LONG VARCHAR, geom AS ST_GeomFromText(gx)) FROM STDIN;
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> 1|POLYGON((31 74,8 70,8 50,36 53,31 74))
>> \.
=> SELECT STV_Create_Index(gid, geom USING PARAMETERS index='my_polygons_1', overwrite=true,
max_mem_mb=256) OVER() FROM pols;
type | polygons | SRID | min_x | min_y | max_x | max_y | info
----------+----------+------+-------+-------+-------+-------+------
GEOMETRY | 1 | 0 | 8 | 50 | 36 | 74 |
(1 row)
=> SELECT STV_Intersect(12.5683, 55.6761 USING PARAMETERS index = 'my_polygons_1');
STV_Intersect
---------------
1
(1 row)
使用 GEOMETRY 列，返回匹配多边形的 gid 或 NULL：
=> CREATE TABLE polygons (gid INT, geom GEOMETRY(700));
CREATE TABLE
=> COPY polygons (gid, gx filler LONG VARCHAR, geom AS ST_GeomFromText(gx)) FROM stdin delimiter '|';
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> 1|POLYGON((-31 74,8 70,8 50,-36 53,-31 74))
>> 2|POLYGON((-38 50,4 13,11 45,0 65,-38 50))
>> 3|POLYGON((-18 42,-10 65,27 48,14 26,-18 42))
>> \.
=> SELECT STV_Create_Index(gid, geom USING PARAMETERS index='my_polygons', overwrite=true,
max_mem_mb=256) OVER() FROM polygons;
type | polygons | SRID | min_x | min_y | max_x | max_y | info
----------+----------+------+-------+-------+-------+-------+------
GEOMETRY | 3 | 0 | -38 | 13 | 27 | 74 |
(1 row)
=> CREATE TABLE points (gid INT, geom GEOMETRY(700));
CREATE TABLE
=> COPY points (gid, gx filler LONG VARCHAR, geom AS ST_GeomFromText(gx)) FROM stdin delimiter '|';
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> 100|POINT(-1 52)
>> 101|POINT(-20 0)
>> 102|POINT(-8 25)
>> 103|POINT(0 0)
>> 104|POINT(1 5)
>> 105|POINT(20 45)
>> 106|POINT(-20 5)
>> 107|POINT(-20 1)
>> \.
=> SELECT gid AS pt_gid, STV_Intersect(geom USING PARAMETERS index='my_polygons') AS pol_gid
FROM points ORDER BY pt_gid;
pt_gid | pol_gid
--------+---------
100 | 1
101 |
102 | 2
103 |
104 |
105 | 3
106 |
107 |
(8 rows)