I must to recognize that today I did not research further about that, I just remember something about convex hull from my scientific research background. Anyway in my case if the convex hull of the streets table doesn't work in the straight manner, I still can make a new table containing first and last point of every line. A convex hull over them should do the work.
On Mon, May 3, 2010 at 1:14 PM, Martin Davis <[email protected]>wrote: > I believe that the convex hull of a set of lines is the same as the convex > hull of the vertices of the lines. So it should do what you want. > > But if you have a reference showing otherwise I'd be interested to see it. > Oscar Zamudio wrote: > >> ha, ha!!, >> My knowledge come from Maths ,and certainly not from Postgis!. The concept >> of Convex Hull (in algorithms and math fields) is always applied to set of >> points and I remember there was a big challenge to find a good method for >> lines (some years ago). But I don't mind Math anymore, if this function >> works to solve my problem, it will be ok for me. >> I will let you know later about my results. >> >> On Mon, May 3, 2010 at 11:29 AM, strk <[email protected]> wrote: >> >> >> >>> On Mon, May 03, 2010 at 11:18:03AM -0300, Oscar Zamudio wrote: >>> >>> >>>> Thanks strk, >>>> As far as I know convex hull basically applies to a collection of >>>> >>>> >>> points..., >>> >>> >>>> nevertheless, I will try with my set of lines. >>>> >>>> >>> How far does your knowledge come from ? :) >>> http://postgis.refractions.net/docs/ST_ConvexHull.html >>> >>> --strk; >>> >>> () Free GIS & Flash consultant/developer >>> /\ http://strk.keybit.net/services.html >>> _______________________________________________ >>> postgis-users mailing list >>> [email protected] >>> http://postgis.refractions.net/mailman/listinfo/postgis-users >>> >>> >>> >> >> ------------------------------------------------------------------------ >> >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > > -- > Martin Davis > Senior Technical Architect > Refractions Research, Inc. > (250) 383-3022 > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users >
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