PostGIS之空间关系

1. 概述

PostGIS 是PostgreSQL数据库一个空间数据库扩展，它添加了对地理对象的支持，允许在 SQL 中运行空间查询

PostGIS官网：About PostGIS | PostGIS

PostGIS官方教程：PostGIS 简介 — Introduction to PostGIS

PostGIS相关教程：文章目录汇总 - 知乎 (zhihu.com)

本文基于官方教程描述PostGIS中的空间关系

数据准备可参考:

• PostGIS教程三：加载空间数据 - 知乎 (zhihu.com)
• 5. Loading spatial data — Introduction to PostGIS

数据介绍可参考:

• PostGIS教程四：关于教程使用的数据 - 知乎 (zhihu.com)
• 6. About our data — Introduction to PostGIS

2. 空间关系

2.1 空间相等

空间相等即所有点坐标相同，使用的函数主要为：

• ST_Equals (A, B) Tests if two geometries include the same set of points

这里先查询一个点的空间位置，再通过查空间位置得到相等的点

--  先查询一个点的空间位置再通过查空间位置相等的点
SELECT name, geom FROM nyc_subway_stations WHERE name = 'Broad St';

得到Broad St的geom: 0101000020266900000EEBD4CF27CF2141BC17D69516315141

SELECT name, geom FROM nyc_subway_stations WHERE ST_Equals(geom, '0101000020266900000EEBD4CF27CF2141BC17D69516315141');

2.2 空间相交

空间相交即空间物体存在交集，空间相离即不存在交集，使用的函数主要为:

• ST_Intersects (A, B)Tests if two geometries intersect (they have at least one point in common)
• ST_Disjoint (A, B) Tests if two geometries have no points in common
• ST_Crosses (g1, g2) Tests if two geometries have some, but not all, interior points in common
• ST_Overlaps (A, B) Tests if two geometries have the same dimension and intersect, but each has at least one point not in the other

查询与Broad St相交的社区，即所在的社区：

SELECT name, boroname
FROM nyc_neighborhoods
WHERE ST_Intersects(geom, '0101000020266900000EEBD4CF27CF2141BC17D69516315141');

查询与Broad St相离的社区：

SELECT name, boroname
FROM nyc_neighborhoods
WHERE ST_Disjoint(geom, '0101000020266900000EEBD4CF27CF2141BC17D69516315141');

• 注意：ST_Disjoint和NOT ST_Intersects相同，但是NOT ST_Intersects由于使用空间索引速度更快

2.3 空间相接

空间相接即空间物体接触在一起但没有相交，使用的函数主要为：

• ST_Touches (A, B) Tests if two geometries have at least one point in common, but their interiors do not intersect

查询与Financial District相接的社区：

SELECT name, boroname
FROM nyc_neighborhoods
WHERE ST_Touches(geom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

2.4 空间包含

空间包含即一个空间物体包含在另一个物体内，主要使用的函数有：

• ST_Within (A, B) Tests if every point of A lies in B, and their interiors have a point in common
• ST_Contains (geomA, geomB) Tests if every point of B lies in A, and their interiors have a point in common

查询包含Broad St的社区：

SELECT name, boroname
FROM nyc_neighborhoods
WHERE ST_Contains(geom, '0101000020266900000EEBD4CF27CF2141BC17D69516315141');

2.5 空间相离

空间相离即Disjoint，前面已叙述有ST_Disjiont函数，这里主要叙述判断相离距离，主要函数有：

• ST_Distance (A, B) Returns the distance between two geometry or geography values.
• ST_DWithin(A, B, distance) Tests if two geometries are within a given distance

查询距离Broad St的10米内的街道：

SELECT name
FROM nyc_streets
WHERE ST_DWithin(geom, '0101000020266900000EEBD4CF27CF2141BC17D69516315141', 10);

3. 参考资料

[1]11. Spatial Relationships — Introduction to PostGIS

[2]PostGIS教程八：空间关系 - 知乎 (zhihu.com)

[3]PostGIS 3.3.3dev Manual

[4]PostGIS Cheat Sheet