对不起,标题乏善可陈,但很难描述......
假设我有两个表(CAD 和 cad_polygon(...
CAD 和 cad_polygon共享彼此相关的同一列 (cad_pid(...
CAD 具有以下列:cad_pid、jrsdctn_id
同时,cad_polygon具有以下列:cad_pid、ogc_fid wkb_geometry
现在,我正在处理的以下查询(半天尝试(根据度数从长纬度坐标中选择一个宗地,从明显较小的多边形子集中,它找到它们与给定的长纬度坐标的距离(以米为单位(,然后仅显示质心在长纬度坐标 500m 以内的多边形。
SELECT SUBQUERY.cad_pid, SUBQUERY.ogc_fid, SUBQUERY.dist_meters,
SUBQUERY.wkb_geometry FROM (
SELECT cad_pid, ogc_fid,
CAST(ST_Distance_Sphere(
ST_Centroid(wkb_geometry),
ST_GeomFromText(
'POINT(00.0000 -00.0000)',
900914)
) AS numeric
) AS dist_meters, wkb_geometry
FROM cad_polygon
WHERE ST_DWithin(
ST_Centroid(wkb_geometry),
ST_GeomFromText(
'POINT(00.0000 -00.0000)',
900914),
0.01)
ORDER BY dist_meters ASC
) AS SUBQUERY
WHERE SUBQUERY.dist_meters < 500;
我想添加到其中并使用此查询吐出的列表,加入我的另一个表 (cad(,以便我可以为每个结果行提供额外的列"jrsdctn_id"......即:
示例数据为: 计算机辅助设计:
cad_pid | jrsdctn_id
0001 | abc123
0002 | def456
0003 | dhk778
0004 | dsk730
cad_polygon:
cad_pid | ogc_fid | wkb_geometry
0001 | ht0101 | 67686687601010000200063D7987FF15ASD1518541DAW
0002 | hz4561 | 435453457601010000200063D7987FF15ASDFW4GF8DE4
0003 | yv0301 | 2626WD687601010000200063D7987FF15ASD1WE851D4D
0004 | vt9701 | D484DW4D8441D8W1C684V63D7987FF15ASD1D7DW4848D
预期成果:
cad_pid | jtsdctn_id | ogc_fid | dist_meters | wkb_geometry
0002 | def456 | hz4561 | 192.769 | 43545...
0004 | dsk730 | vt9701 | 342.548 | D484D...
如果有一些sql向导可以提供帮助,那就太好了!
有点晚了,当然,关于JOIN
的公认答案是绝对正确的,但这实际上与GIS密切相关,它的意识最终使您更轻松:
您似乎正在使用自定义CRS或ogr2ogr(或任何GDAL/OGR函数(在PostGIS的spatial_ref_sys表中找不到匹配的SRID/投影;但是,任何使用LonLat作为球面/shperoid代数输入的PostGIS函数将始终假定您的坐标在EPSG:4326(WGS84(中。
如果您的 LonLat 与 WGS84 的不完全匹配,则结果将关闭!
现在,PostGIS 还具有地理类型,它再次假定 EPSG:4326 坐标,如果与这些功能一起使用,它将隐式使用米作为单位,如果与默认ST_Distance
参数一起使用,则将在 WGS84 椭球体上进行计算(更精确,但比use_spheroid := false
稍慢,后者将根据球体计算距离(。
考虑到这一点,您的查询可以表示为:
WITH
pt AS (
SELECT ST_Transform(ST_SetSRID(ST_MakePoint(0, 0), 900914), 4326)::geography AS geog
),
ctr AS (
SELECT *,
ST_Transform(ST_Centroid(wkt_geometry), 4326)::geography AS geog
FROM cad_polygon
)
SELECT ctr.cad_pid,
cad.jtsdctn_id,
ctr.ogr_fid,
ST_Distance(ctr.geog, pt.geog) AS distance_meter,
ctr.wkt_geometry
FROM ctr
JOIN cad
ON ctr.cad_pid = cad.cad_pid
WHERE ST_DWithin(ctr.geog, pt.geog, 500)
ORDER BY distance_meter ASC;
请注意使用 CTE 来避免对每个已处理的行进行转换/转换,并使事情更加结构化。
我就是不能放手...
您可以使用 JOIN
SELECT SUBQUERY.cad_pid, SUBQUERY.ogc_fid, SUBQUERY.dist_meters,
SUBQUERY.wkb_geometry, SUBQUERY.jrsdctn_id FROM (
SELECT cad_pid, ogc_fid,
CAST(ST_Distance_Sphere(
ST_Centroid(wkb_geometry),
ST_GeomFromText(
'POINT(00.0000 -00.0000)',
900914)
) AS numeric
) AS dist_meters, wkb_geometry, cad.jrsdctn_id
FROM cad_polygon
INNER JOIN cad on cad.cad_pid = cad_polygon.cad_pid
WHERE ST_DWithin(
ST_Centroid(wkb_geometry),
ST_GeomFromText(
'POINT(00.0000 -00.0000)',
900914),
0.01)
ORDER BY dist_meters ASC
) AS SUBQUERY
WHERE SUBQUERY.dist_meters < 500;
或者最好在外部添加联接
SELECT SUBQUERY.cad_pid
, SUBQUERY.ogc_fid
, SUBQUERY.dist_meters,
SUBQUERY.wkb_geometry, cad.jrsdctn_id
FROM (
SELECT cad_polygon.cad_pid, ogc_fid,
CAST(ST_Distance_Sphere(
ST_Centroid(wkb_geometry),
ST_GeomFromText(
'POINT(00.0000 -00.0000)',
900914)
) AS numeric
) AS dist_meters
, wkb_geometry
FROM cad_polygon
WHERE ST_DWithin(
ST_Centroid(wkb_geometry),
ST_GeomFromText(
'POINT(00.0000 -00.0000)',
900914),
0.01)
ORDER BY dist_meters ASC
) AS SUBQUERY
INNER JOIN cad on cad.cad_pid = SUBQUERY.cad_pid
WHERE SUBQUERY.dist_meters < 500;