[postgis-users] Help with Query

[Martin Davis]

Be aware that Points have only an interior, not a boundary.  So 
ST_Touches(line, point) is only true if the point coincides with an 
endpoint of the line.

Perhaps ST_Touches(s1.geom, s2.geom)  might produce some results?

On 1/11/2013 4:20 PM, Clifford Snow wrote:
> First off, I'm a new at Postgis so please let me know if the right 
> response to my question is RTFM.
>
> I have the NHD streams for my state that I want to import into 
> OpenStreetMap. When I select just the streams that I'm interested in I 
> find that there are numerous short linestrings (2 nodes) that I'd like 
> to get rid of. These linestrings are only connected at one end.  It 
> seems like ST_Touches() would find them. I did a simple query of
>
> SELECT s1.gid, s2.gid from flowlines s1, flowlines s2 WHERE 
> ST_Touches(s1.geom,ST_PointN(s2.geom,1) and s2.pointcount = 2;
>
> It returns 0 rows. Changing the point on s2.geom to 0 makes no 
> difference.
>
> Anyone have a suggestion of how I find 2 node streams that connect to 
> another stream?
>
> -- 
> Clifford
>
> OpenStreetMap: Maps with a human touch
>
>
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