如何使用 ST_Touches 获取接触几何体的交集长度

Question

我正在尝试在 Postgis 中开发一个查询，它可以解决这个问题：

我有一个几何图形，我想知道哪个多边形与它接触，这个几何图形的接触面积最大。在我识别出这个多边形之后，我将在特定列中获取它的值，并将该值放在同一列中但在我的几何中。

有人知道我该怎么做吗？我是 postgresql/postgis.

的新用户

Answer 1

正如@JGH 在评论中指出的那样，如果您使用 ST_Touches alone. What you can do is to filter out only the geometries that do touch your reference geometry and then use ST_Intersection to get the intersection area, so that you can finally calculate the length of the intersection with ST_Length.

，重叠区域将为零

数据样本

上面描述的几何值在 CTE 内：

WITH j (id,geom) AS (
  VALUES 
  (1,'POLYGON((-4.64 54.19,-4.59 54.19,-4.59 54.17,-4.64 54.17,-4.64 54.19))'),
  (2,'POLYGON((-4.59 54.19,-4.56 54.19,-4.56 54.17,-4.59 54.17,-4.59 54.19))'),
  (3,'LINESTRING(-4.65 54.19,-4.57 54.21)'),
  (4,'POLYGON((-4.66 54.21,-4.60 54.21,-4.60 54.20,-4.66 54.20,-4.66 54.21))'),
  (5,'POINT(-4.57 54.20)')
)
SELECT 
  id, 
  ST_Length(
    ST_Intersection(
      geom,
      'POLYGON((-4.62 54.22,-4.58 54.22,-4.58 54.19,
                -4.62 54.19,-4.62 54.22))')) AS touch_length
FROM j
WHERE 
  ST_Touches(
    geom,
    'POLYGON((-4.62 54.22,-4.58 54.22,-4.58 54.19,
              -4.62 54.19,-4.62 54.22))')
ORDER BY touch_length DESC
LIMIT 1;

 id |    touch_length     
----+---------------------
  1 | 0.03000000000000025
(1 Zeile)

如何使用 ST_Touches 获取接触几何体的交集长度

How to get the intersection length of touching geometries with ST_Touches

sql

postgresql

postgis