## Name

ST_Touches — Tests if two geometries have at least one point in common, but their interiors do not intersect

## Synopsis

`boolean `**ST_Touches**(

geometry `A`, geometry `B``)`

;

## Description

Returns `TRUE`

if A and B intersect, but their interiors do not intersect. Equivalently, A and B have at least one point in common, and the common points lie in at least one boundary. For Point/Point inputs the relationship is always `FALSE`

, since points do not have a boundary.

In mathematical terms: *ST_Touches(A, B) ⇔ (Int(A) ⋂ Int(B) ≠ ∅) ∧ (A ⋂ B ≠ ∅) *

This relationship holds if the DE-9IM Intersection Matrix for the two geometries matches one of:

FT*******

F**T*****

F***T****

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This function automatically includes a bounding box comparison that makes use of any spatial indexes that are available on the geometries. To avoid using an index, use `_ST_Touches` instead. |

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Enhanced: 3.0.0 enabled support for `GEOMETRYCOLLECTION` |

This method implements the OGC 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

## Examples

The `ST_Touches`

predicate returns `TRUE`

in the following examples.

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)