[postgis-users] How to check if two linestring are near to each other

[Åsmund Tokheim]

Hi

I think you should be able to use hausdorff distance
http://postgis.net/docs/ST_HausdorffDistance.html to recognize that the
green, red and blue lines in your image are all similar. This method will
fail to recognize shared portions of a path (e.g. if the blue line at some
point diverges from the red and green line), but I'm not sure if this is a
requirement for your task

Åsmund


On Sat, Apr 12, 2014 at 9:41 PM, Raghavan Krishnasamylakshmanaperumal <
rkrish20 at uic.edu> wrote:

> Hi,
>
> I have formed a graph using my GPS traces of running/biking activities in
> which I have many edges representing the same path. For example every time
> I run from node-A to node-B my GPS traces are noted close to each other
> like the red,green,blue lines in the attached image. Actually those 3 lines
> are same(representing the same path), so I want to detect such linestrings
> automatically and keep only one linestring and ignore others. Is there any
> way in PostGIS which can help me to detect the nearness/closeness of the
> linestrings?
>
> --
> Thanks and Regards,
> Raghavan KL
>
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