Name
ST_IsSimple — Tests if a geometry has no points of self-intersection or self-tangency.
Synopsis
boolean ST_IsSimple(geometry geomA);
Descrizione
Returns true if this Geometry has no anomalous geometric points, such as self-intersection or self-tangency. For more information on the OGC's definition of geometry simplicity and validity, refer to "Ensuring OpenGIS compliance of geometries"
![[Note]](../images/note.png)
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SQL-MM defines the result of ST_IsSimple(NULL) to be 0, while PostGIS returns NULL. |
Questo metodo implementa le OGC Simple Features Implementation Specification for SQL 1.1. s2.1.1.1
Questo metodo implementa la specifica SQL/MM. SQL-MM 3: 5.1.8
Questa funzione supporta il 3d e non distrugge gli z-index.
Esempi
SELECT ST_IsSimple(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))'));
st_issimple
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f
(1 row)
SELECT ST_IsSimple(ST_GeomFromText('LINESTRING(1 1,2 2,2 3.5,1 3,1 2,2 1)'));
st_issimple
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f
(1 row)