[OSM-dev] Determining if two linestrings are "similar"

Jukka Rahkonen jukka.rahkonen at latuviitta.fi
Mon Jan 7 10:37:07 GMT 2013


OpenJUMP has two plugins for matching topologies



They are written by good experts and they come with source code and
documentation and I guess they are worth having a look.

-Jukka Rahkonen-

Paweł Paprota wrote:
> Hi all,
> Here's an interesting problem I'm trying to tackle now in OWL...
> You have two linestrings and the task is to determine if they are
> "similar" or not. Similar means spatially "the same" as looked at by
> human eye at zoom level 18 on a slippy map :-)
> Note that the two geometries are not equal in ST_Equals sense. They
> don't have to intersect but can intersect or even be almost the same
> save for one node slightly moved.
> OWL right now shows some changes that in fact are non-changes - e.g.
> using simplify way feature of JOSM changes way nodes but preserves (or
> only very slightly changes) way geometry. It is not a change worth
> processing and showing to the user.
> I tried ST_HausdorffDistance[1] from PostGIS but for now it does not
> yield useful results or maybe I am misinterpreting them.
> Any ideas?
> http://www.postgis.org/docs/ST_HausdorffDistance.html
> Paweł
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