名前
ST_IsCollection — Returns true if all exterior rings are oriented counter-clockwise and all interior rings are oriented clockwise.
概要
boolean ST_IsEmpty(geometry geomA);
説明
Returns true if all polygonal components of the input geometry use a counter-clockwise orientation for their exterior ring, and a clockwise direction for all interior rings.
ジオメトリが、空のジオメトリコレクション、ポリゴン、ポイント等の場合に、trueを返します。
![[注記]](images/note.png) | |
Closed linestrings are not considered polygonal components, so you would still get a true return by passing a single closed linestring no matter its orientation. |
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If a polygonal geometry does not use reversed orientation for interior rings (i.e., if one or more interior rings are oriented in the same direction as an exterior ring) then both ST_IsPolygonCW and ST_IsPolygonCCW will return false. |
This function supports 3d and will not drop the z-index.
This function supports M coordinates.