PostGIS 中最近邻搜索错误

Question

我正在尝试编写一个 PostGIS 最近邻查询，其中选择了一组坐标并确定了距最近的洪水多边形的距离。然后我想将距离分类为“外部，'CLOSE' 或 'INSIDE':

WITH 
  point_loc (geom) AS ( 
    SELECT ST_SetSRID(ST_MakePoint(531673.0, 180848.2),27700) ),
  distances (gid, distance) AS (
    SELECT  
      fl.gid,
      ST_Distance(fl.geom, p.geom) AS distance
    FROM
      point_loc p, flooding fl
    WHERE ST_DWithin(p.geom, fl.geom, 400)
  SELECT 
    gid,
    CASE WHEN distance > 300 THEN 'OUTSIDE'
         WHEN distance > 50 AND <= 300 THEN 'CLOSE'
         ELSE 'INSIDE'
    END as flood_result
  FROM distances;

我在最后的 SELECT 调用中不断收到语法错误。谁能看出我做错了什么？

Answer 1

您的第二个 CTE 缺少右括号。

这一行： WHERE ST_DWithin(p.geom, fl.geom, 400)

应该是： WHERE ST_DWithin(p.geom, fl.geom, 400) )

PostGIS 中最近邻搜索错误

Error in nearest neighbor search in PostGIS

postgresql

postgis

nearest-neighbor