[postgis-users] identifying similar geometries

[Charles Galpin]

Some background - I have a set of line geometries (happens to be Navteq streets/links) which we have used the ids of certain links for various reasons (like we have stored routes based on start/end link, or other edits to enhance the data).  We are looking at upgrading the data and have found that for a fairly significant number of links, navteq have retired the old link ids and replaced them with new ones.  In some cases it appears the geometry has just changed slightly but has the same start/end and length. In others they have split the link into two or more new links, etc.

Because we have some link ids we depend on, I need to map the old ids to the new ones and I am looking for suggestions.  I can identify the essentially identical ones with the ~= operator.   I can identify some with the same start point and some other identifying attributes.  But there are still a number that I'd like to do the equivalent of visually overlaying them and seeing they are the same link.

Does anyone know of a way to say "this geometry looks [a lot] like this one"?  Maybe make a small buffer around one and see if the other is contained within it (and do it int he opposite order to catch both shrinking and expanding (not sure any have grown).

thanks,
charles