[postgis-users] How to extract common linestring of polyon and linestring
woodbri at swoodbridge.com
Wed Mar 11 10:08:24 PDT 2009
akrherz at iastate.edu wrote:
> Firstly, PostGIS continues to rock! Thanks so much for this software...
> My question is that I have a rivers linestring table and a political
> boundaries table (US counties) polygon. I am wishing to extract the
> portion of the river geometry that lies along a county border. Of
> course, these two layers don't have the same individual point precision,
> so I suspect some buffering, simplification is necessary. I am not
> seeking anything exact, but something like if the river and a county
> border are within a few hundred meters of each other for some distance
> along the river and county border.
> I can't seem to figure out which functions could accomplish this task,
> or if it is possible. Currently, I have no issue finding points of
> intersection, so perhaps that is part of the solution that is staring me
> in the face :)
You might try something like:
How about buffering the country polygon by your tolerance and then get
the results of the buffered country and the river.
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