ST_Touches — Returns TRUE
if the geometries have at least one point in common,
but their interiors do not intersect.
boolean ST_Touches(
geometry
g1, geometry
g2)
;
Returns TRUE
if the only points in common between
g1
and g2
lie in the union of the
boundaries of g1
and g2
.
The ST_Touches
relation applies
to all Area/Area, Line/Line, Line/Area, Point/Area and Point/Line pairs of relationships,
but not to the Point/Point pair.
In mathematical terms, this predicate is expressed as:
The allowable DE-9IM Intersection Matrices for the two geometries are:
FT*******
F**T*****
F***T****
Do not call with a |
This function call will automatically include a bounding box
comparison that will make use of any indexes that are available on
the geometries. To avoid using an index, use |
This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 // s2.1.13.3
This method implements the SQL/MM specification. SQL-MM 3: 5.1.28
The ST_Touches
predicate returns TRUE
in all the following illustrations.
SELECT ST_Touches('LINESTRING(0 0, 1 1, 0 2)'::geometry, 'POINT(1 1)'::geometry); st_touches ------------ f (1 row) SELECT ST_Touches('LINESTRING(0 0, 1 1, 0 2)'::geometry, 'POINT(0 2)'::geometry); st_touches ------------ t (1 row)