ST_CollectionExtract—给定(多)几何,返回仅由指定类型的元素组成的(多)几何。 ST_CollectionExtract— Given a (multi)geometry, return a (multi)geometry consisting only of elements of the specified type. ST_CollectionHomogenize—给定一个几何集合,返回内容的“最简单”表示。 ST_CollectionHomogenize— Given ...
ST_AddPoint—将点添加到LineString。 ST_CollectionExtract—给定(多)几何,返回仅由指定类型的元素组成的(多)几何。 ST_CollectionHomogenize—给定几何集合,返回内容的“最简单”表示形式。 ST_CurveToLine—将包含曲线的几何转换为线性几何。 ST_FlipCoordinates—返回X和Y轴已翻转的几何版本。 ST_Force2D—将几何...
SELECT ST_AsText(ST_LineMerge(ST_GeomFromText('MULTILINESTRING((-29 -27,-30 -29.7,-36 -31,-45 -33),(-45 -33,-46 -32))'))); 5、ST_CollectionExtract 给定一个(Milti)几何对象,返回一个(Milti)几何对象,只能包含元素指定类型的。几何形状开头没有指定的类型将被忽略。如果开头没有正确的几何...
存在问题:拓扑检查后出现很多小面:ST_Buffer(geometry g1, float radius 12、_of_buffer, text buffer_style_parameters=)优化方案优化方案:设置拓扑后出现结果的面积阈值Note:正负值ST_Buffer处理后图形的有效性验证问题(ST_IsValid, st_makeValid)相交后结果是否为面,提取对应类型的图形( ST_CollectionExtract )...
WITH RECURSIVE source (rownum, geom, ret) AS ( SELECT row_number() OVER (ORDER BY name ASC), ST_Multi(geom), ARRAY[name] FROM test ), r (rownum, geom, ret, incroci) AS ( SELECT rownum, geom, ret, 0 FROM source UNION ALL SELECT s.rownum, ST_CollectionExtract(ST_Intersection(s....
➢Thefunctionsupportssplittingalineby(multi)point,(multi)lineor(multi)polygonboundary,a(multi)polygonbyline.Thereturnedgeometryisalwaysacollection.➢ThinkofthisfunctionastheoppositeofST_Union.TheoreticallyapplyingST_Uniontotheelementsofthereturnedcollectionshouldalwaysyieldtheoriginalgeometry.切割前 切割后 ST_...
postgres=# select extract(epoch from now()); date_part --- 1528347342.99521 (1 row) postgres=# select ST_MakeLine(ST_MakePointM(-350,300,1528347341),ST_MakePointM(-410,490,1528347342)); st_makeline --- 0102000040020000000000000000E075C00000000000C07240000040B32EC6D6410000000000A079C00000000000A...
functions available, and it is hard to get past simple things like ST_Intersects and ST_DWithin to the next level.But once you get to the next level, youʼll find that PostGIS is as powerful (or more)than many desktop GIS systems.My son suggested the following topical breakdown.
ST_AddPoint、ST_Affine、ST_Force2D、ST_Force3D、ST_Force3DZ、ST_Force3DM、ST_Force4D、ST_ForceCollection、ST_ForceSFS、ST_ForceRHR、ST_LineMerge、ST_CollectionExtract、ST_CollectionHomogenize、ST_Multi、ST_RemovePoint、ST_Reverse、ST_Rotate、ST_RotateX、ST_RotateY、ST_RotateZ、ST_Scale、ST_Seg...
documentation description says: Returns the polygon part of an alpha shape. But instead I am getting a geometry_collection instead. I can solve it with st_CollectionExtract, but I m wondering if this is the expected behaviour. Alexandre Neto ...