You might try something like:
select a.gid, b.gid,
distance(makepoint(x,y), st_intersection(a.the_geom, b.the_geom)
as dist
from lines a, lines b
where st_expand(makepoint(x,y), max_dist) && a.the_geom and
st_expand(makepoint(x,y), max_dist) && b.the_geom and
st_intersects(a.the_geom, b.the_geom);
You will like need to change this based on whatever SRID you are using.
I have not tried this, but maybe it will get you started.
-Steve
PS: please keep the list CC on this, there are other that can help and
profit from the responses.
On 8/24/2010 1:34 PM, [email protected] wrote:
My data isn't noded and when I said "near" is by a maximun distance. If
I had a line A and line B how I can do to know if a point is near of the
intersection of this lines?
El 24/08/2010 14:04, Stephen Woodbridge <[email protected]> escribió:
> On 8/24/2010 11:19 AM, Ricardo Vilella wrote:
>
>
> I have a layer with lines representing the streets of a city, how I can
>
> do to find if a point is near an intersection of two streets?
>
>
>
>
> I think we need a little more information:
>
>
>
> How do you want to define "near"? by some maximum distance?
>
> What is an intersection?
>
> A. if you data is noded, then intersections are defined by a node
that has two or more segments with different names.
>
> B. if not noded then you have compute all the segment segment
intersections in the area "near" the point.
>
>
>
> -Steve
>
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