ST_Touches — Return true if raster rastA and rastB have at least one point in common but their interiors do not intersect.
boolean ST_Touches(
                        raster 
                        rastA
                    , 
                        integer 
                        nbandA
                    , 
                        raster 
                        rastB
                    , 
                        integer 
                        nbandB
                    );
boolean ST_Touches(
                        raster 
                        rastA
                    , 
                        raster 
                        rastB
                    );
Return true if raster rastA spatially touches raster rastB. This means that rastA and rastB have at least one point in common but their interiors do not intersect. If the band number is not provided (or set to NULL), only the convex hull of the raster is considered in the test. If the band number is provided, only those pixels with value (not NODATA) are considered in the test.
![]()  | |
This function will make use of any indexes that may be available on the rasters.  | 
![]()  | |
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g. ST_Touches(ST_Polygon(raster), geometry).  | 
Availability: 2.1.0