使用postgis选择转储的多部分几何到数组中
[英]Select dumped multipart geometries into array with postgis
问题描述
i'm running the following query on a table of multipart polygons: 
我在多部分多边形表上运行以下查询：
SELECT id, surface_cnrtd, array_agg(igeom)
FROM (select id, st_astext(st_pointonsurface(geom)) as surface_cnrtd,
st_dump(geom) as igeom from my_table where id = '10020080') sub
GROUP BY dauid, surface_cnrtd;
I would like to return a row with the (id i've indicated, a point geometry for the pointonsurface, an array of the path and geometries for each individual part of the multipart polygon). 我想返回一行（id我已经指出，一个点子几何表面的点几何，一个多边形多边形的每个单独部分的路径和几何的数组）。 I know that polygon 10020080 is mulitpart because if I change the query to this: 我知道多边形10020080是mulitpart，因为如果我将查询更改为：
SELECT id, surface_cnrtd, array_agg(igeom)
FROM (select id, st_astext(st_pointonsurface(geom)) as surface_cnrtd,
(st_dump(geom)).path as igeom from my_table where id = '10020080') sub
GROUP BY dauid, surface_cnrtd;
it returns this: 它返回：
('10020080', 'POINT(-54.3834654151038 47.6947475)', [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19]])
but when I run the original query my array has only the 1st geometry, like this: 但是当我运行原始查询时，我的数组只有第一个几何，如下所示：
('10020080', 'POINT(-54.3834654151038 47.6947475)', '{"({1},0103000020E61000000..........................BC0F110C64FE3E64740)"}
can anyone help me get the paths and the geometry of the dumped polygon into an array? 任何人都可以帮助我将转储多边形的路径和几何形状放入数组中吗？
1 个解决方案
解决方案1
0 2018-06-19 16:47:21
You can put the first query into a CTE (aka WITH clause) and then aggregate the dumped geometries as you wish: 您可以将第一个查询放入CTE （也称为WITH子句），然后根据需要聚合转储的几何：
WITH j AS(
SELECT 1 AS id, 'POINT(-54.3834654151038 47.6947475)'::geometry AS surface_cnrtd,
ST_Dump('MULTIPOLYGON (((30 20, 45 40, 10 40, 30 20)),
((15 5, 40 10, 10 20, 5 10, 15 5)))') AS geom
)
SELECT j.id, ST_AsText(j.surface_cnrtd), array_agg(j.geom)
FROM j
GROUP BY j.id, j.surface_cnrtd;
id | st_astext | array_agg
----+-------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 | POINT(-54.3834654151038 47.6947475) | {"({1},010300000001000000040000000000000000003E40000000000000344000000000008046400000000000004440000000000000244000000000000044400000000000003E400000000000003440)","({2},010300000001000000050000000000000000002E4000000000000014400000000000004440000000000000244000000000000024400000000000003440000000000000144000000000000024400000000000002E400000000000001440)"}
(1 Zeile)
If you wanna stick to your syntax ... 如果你想坚持你的语法......
SELECT id, ST_AsText(surface_cnrtd), array_agg(igeom)
FROM (SELECT 1 AS id, 'POINT(-54.3834654151038 47.6947475)'::geometry AS surface_cnrtd,
ST_Dump('MULTIPOLYGON (((30 20, 45 40, 10 40, 30 20)),
((15 5, 40 10, 10 20, 5 10, 15 5)))') as igeom) sub
GROUP BY id, surface_cnrtd;
id | st_astext | array_agg
----+-------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 | POINT(-54.3834654151038 47.6947475) | {"({1},010300000001000000040000000000000000003E40000000000000344000000000008046400000000000004440000000000000244000000000000044400000000000003E400000000000003440)","({2},010300000001000000050000000000000000002E4000000000000014400000000000004440000000000000244000000000000024400000000000003440000000000000144000000000000024400000000000002E400000000000001440)"}
(1 Zeile)
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