Description

Returns TRUE if geometry A and B "spatially overlap". Two geometries overlap if they have the same dimension, their interiors intersect in that dimension. and each has at least one point inside the other (or equivalently, neither one covers the other). The overlaps relation is symmetric and irreflexive.

In mathematical terms: ST_Overlaps(A, B) ⇔ ( dim(A) = dim(B) = dim( Int(A) ⋂ Int(B) )) ∧ (A ⋂ B ≠ A) ∧ (A ⋂ B ≠ B)

	Cette fonction inclut une comparaison de la boîte englobante qui utilise tous les index disponibles sur les géométries. Pour éviter l'utilisation d'un index, utilisez la fonction _ST_Overlaps.

Effectué par le module GEOS

	Amélioration : 3.0.0 a permis la prise en charge de GEOMETRYCOLLECTION

NOTE : il s'agit de la version "autorisée" qui renvoie un booléen et non un entier.

Cette méthode implémente la spécification OGC Simple Features Implementation Specification for SQL 1.1.

s2.1.1.2 // s2.1.13.3

Cette méthode implémente la spécification SQL/MM.

SQL-MM 3: 5.1.32

Exemples

ST_Overlaps renvoie TRUE dans les situations suivantes :

MULTIPOINT / MULTIPOINT

LINESTRING / LINESTRING

POLYGON / POLYGON

Un point sur une LineString est contenu, mais comme il a une dimension inférieure, il ne se chevauche pas et ne se croise pas.

SELECT ST_Overlaps(a,b) AS overlaps,       ST_Crosses(a,b) AS crosses,
       ST_Intersects(a, b) AS intersects,  ST_Contains(b,a) AS b_contains_a
FROM (SELECT ST_GeomFromText('POINT (100 100)') As a,
             ST_GeomFromText('LINESTRING (30 50, 40 160, 160 40, 180 160)')  AS b) AS t

overlaps | crosses | intersects | b_contains_a
---------+----------------------+--------------
f        | f       | t          | t

Une chaîne de lignes qui recouvre partiellement un polygone l'intersecte et le traverse, mais ne se chevauche pas car elle a des dimensions différentes.

SELECT ST_Overlaps(a,b) AS overlaps,        ST_Crosses(a,b) AS crosses,
       ST_Intersects(a, b) AS intersects,   ST_Contains(a,b) AS contains
FROM (SELECT ST_GeomFromText('POLYGON ((40 170, 90 30, 180 100, 40 170))') AS a,
             ST_GeomFromText('LINESTRING(10 10, 190 190)') AS b) AS t;

 overlap | crosses | intersects | contains
---------+---------+------------+--------------
 f       | t       | t          | f

Deux polygones qui se croisent mais dont aucun n'est contenu par l'autre se chevauchent, mais ne se croisent pas car leur intersection a la même dimension.

SELECT ST_Overlaps(a,b) AS overlaps,       ST_Crosses(a,b) AS crosses,
       ST_Intersects(a, b) AS intersects,  ST_Contains(b, a) AS b_contains_a,
       ST_Dimension(a) AS dim_a, ST_Dimension(b) AS dim_b,
       ST_Dimension(ST_Intersection(a,b)) AS dim_int
FROM (SELECT ST_GeomFromText('POLYGON ((40 170, 90 30, 180 100, 40 170))') AS a,
             ST_GeomFromText('POLYGON ((110 180, 20 60, 130 90, 110 180))') AS b) As t;

 overlaps | crosses | intersects | b_contains_a | dim_a | dim_b | dim_int
----------+---------+------------+--------------+-------+-------+-----------
 t        | f       | t          | f            |     2 |     2 |       2

Voir aussi

ST_Contains, ST_Crosses, ST_Dimension, ST_Intersects