[postgis-users] Postgis overlapping two linestrings

[Ani Alamo]

Uhm... exactly I have this linestrings:
LINESTRING(2.118932325 41.398745991,2.168720219 41.385631938)
LINESTRING(2.142346041 41.398526436,2.111181541 41.409216161)

intersections gives me:
GeometryCollection: GEOMETRYCOLLECTION EMPTY

intersects gives me:
false

but when I see the line drawn on map I see both lines intersect in a little
"section" (strectch). But really when I use intersects or intersection
functions gives me "unavailable intersection"... and when I use OVERLAPS
function
overlaps(buffer(LINESTRING1, 0.001), buffer(LINESTRING2, 0.001)) also gives
me "false".

Another ideas please??


2013/11/22 James David Smith <james.david.smith at gmail.com>

> Hi Ani,
>
> Have you looked into st_intersects() ? and st_intersection() ?
>
> http://postgis.refractions.net/docs/ST_Intersects.html
>
> James
>
> On 22 November 2013 16:17, Ani Alamo <alamo.ani at gmail.com> wrote:
> > Hi!
> > I need a specific function to get if two linestring overlaps. e.g.
> > Linestring 1 is Point (0, 0) : Point (10, 0) Linestring 2 is Point (0,
> 0) :
> > Point (3, 0)
> >
> > In this case I need "true" result because LineString 1 overlaps in
> different
> > points like 0,0 1,0 2,0 & 3,0. I dont need the common points, I only
> need if
> > two linestring overlaps or not. I tried with this function in postgis...
> >
> > overlaps(buffer(LINESTRING1, 0.001), buffer(LINESTRING2, 0.001))
> > I create a buffer on both linestrings... but muy problem is some times
> works
> > better, some times not.
> >
> > Can you help me please?
> >
> > Thanks!
> >
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