I'm troubling with save of shapes in db. The shapes are steel sheet cuts, with may be holes, therefore are collections. I decided to solve to my self the problem, to allow the easy exportation between pc. But I cannot achive to detect the mirrored shapes. I wrote some very robust code to detect the equality, but doesn't detect the mirrored copies. The nature of the problem impose to detect it, because if a sheet has a good surface, these are different shapes. I would wonder if postgis detect mirrored copies as different copies or also treat them as equal? Ore if somebody can help me with my routine, to detect the equality I wrote an adjacenze matrix of distances between each vertex. If the sum of each row are equal to the new shape the shapes are equal( an extension of a triangle is equal to another if three infos are equal) . But I cannot find a way to define the mirror, if not go throug perverse code and analyze the points.