This topic describes the ST_SharedPaths function. This function returns a collection of paths that are shared by two input geometry objects.

Syntax

geometry  ST_SharedPaths(geometry  lineal1 , geometry  lineal2);

Parameters

Parameter Description
lineal1 The shared path 1.
lineal2 The shared path 2.

Description

  • The objects in the same direction are in the first element of the returned collection, and the objects in the opposite direction are in the second element of the returned collection.
  • The direction of paths in the returned collection is based on the direction of the first input geometry object.

Examples

Results returned by using the default parameter settings:
select ST_AsText(ST_GeometryN(g,1)),ST_AsText(ST_GeometryN(g,2)) from (select ST_SharedPaths('LINESTRING(-1 0,0 0,0 1)'::geometry,'LINESTRING(0 0,0 1,1 1)'::geometry) as g) as t;
         st_astext          |       st_astext
----------------------------+-----------------------
 MULTILINESTRING((0 0,0 1)) | MULTILINESTRING EMPTY
(1 row)