[postgis-users] st_intersects not working

[Sandro Santilli]

On Wed, Feb 11, 2015 at 02:25:08PM -0500, Rhys A.D. Stewart wrote:
> Greetings all,
> 
> I am working on a set of data where I have noded linestrings. All
> linestrings have just two points and the nodes were derived from the
> endpoints.
> 
> I've found one instance where st_intersects and st_equals return the
> incorrect value (AFAICT).
...
> I did a select into a new schema and the same issue occurred. I did an
> `update table set g = st_astext(g)::geometry` and it works fine after that.

Sounds like a small coordinate difference that's not enough to get a digit
printed when converted to text. Compare the HEXWKB to spot the difference.
You can use ST_SnapToGrid to ensure all vertexes fall on the same grid.

--strk;