[pgrouting-users] problems with pgr_pointsAsPolygon

[Vicky Vergara]

Hi Dave,
You are talking about a function who's code has not being "revised"
Currently it use's CGAL alphashape
Actually we want to move it to GEOS (then to postGIS) because it has to do
more with geometries than with graph algorithms, and we can remove CGAL
dependency on pgRouting.
But while we still have it:
Please open an issue, in the issue, post the smallest data possible (can be
a link to a zipped file) where we can reproduce the problem.
Also what happens if you set alpha exactly to 1?

I have this kinda blog in form of an issue:
https://github.com/cvvergara/pgrouting/issues/57

Regards VIcky



On Tue, Oct 9, 2018 at 11:43 AM Dave Potts <mrdapotts at gmail.com> wrote:

> I have a collection of x,y points and I am trying to draw a bounding
> polygon. I was unhappy with the default returned, so I decided to a play
> with the alpha parameter.
>
> I get no result and the value 'NOTICE:  n = 1'
>
> printed on the console,
> My sql is
>
> pgr_pointsAsPolygon('select id,st_x(st_startpoint(the_geom)) as x,
> st_y(st_startpoint(the_geom)) as y from tmp where label=27,5.0);
>  select pgr_version() returns psql (10.5 (Ubuntu 10.5-1.pgdg16.04+1))
> The machine is running postgres 10.5-1
>
> Is there anything wrong with what I am doing? Using an alpha value of 0
> does not generate an error.
>
> regards
>
>
> Dave.
>
>
>
>
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> Pgrouting-users at lists.osgeo.org
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