[postgis-users] Diagram of Voronoï to Squelettisation of polygon

[Daniel Kastl]

Hi Jérôme,

As you said the idea would be to add a function that calculates a skeleton
from a polygon.

Currently pgRouting contains a couple of functions (
http://www.pgrouting.org/docs/1.x/index.html), but all of them require
network data with at least information about "start" and "end" ID of a
linestring. If the information about "start" and "end" ID doesn't exist yet,
you can run a function called "assign_vertex_id". But what you need is
network data.

Your skeleton function now would allow users to add one more step before and
retrieve a network from polygon data. So one could first run the skeleton
function, then the  "assign_vertex_id" function and finally have all the
routing functions available even if the original data was of polygon shape.

pgRouting has it's source code on GitHub (https://github.com/pgRouting/).
The "assign_vertex_id" function is here:
https://github.com/pgRouting/pgrouting/blob/master/core/sql/routing_topology.sql.
Though I'm not sure it wouldn't be a good idea to reorganize this a bit.
Well, I think we might better discuss details on the pgRouting list:
http://lists.osgeo.org/mailman/listinfo/pgrouting-dev

Best regards,
Daniel



2010/12/11 j.rolland <jrmrolland at aol.com>

>
> Hi Daniel,
>
> Of course that I am interested, say me how I can contribute my share.
> As I indicate it in my blog, I can develop a function which turns over the
> skeleton from a polygon. Give me your specifications and I would study
> them.
>
>
> cordially,
> Jérôme
>
>
> Daniel Kastl-3 wrote:
> >
> > Salut Jérôme,
> >
> > Thank you for sharing your blog article!
> > I tried to recall my French from high school and thanks to nice
> > screenshots
> > and code samples I think I could mostly understand.
> >
> > Well, I thought your functions might be an interesting contribution to
> > pgRouting project (http://www.pgrouting.org).
> > We're trying to collect various routing and network analysis related
> > functionality. Some voronoi and skeleton addition would for sure suite
> > well.
> > That way users could build some routable network out of river polygons
> for
> > example. It might also help to build a routable graph for  maritime
> > navigation. Probably there are a lot more use cases.
> >
> > Let me know if you're interested.
> >
> > Daniel
> >
> >
> > 2010/12/9 j.rolland <jrmrolland at aol.com>
> >
> >>
> >> hi,
> >>
> >> I have just set up on my blog at the following address
> >> http://ageoguy.blogspot.com/2010/12/squ… ation.html
> >> http://ageoguy.blogspot.com/2010/12/squ… ation.html  a tutorial (in
> >> french)
> >> which presents an algorithm of surface squelettisation of waterway
> >> (POLYGON).
> >> I provide an example like all the necessary functions and requests which
> >> will enable you to obtain the skeleton of the waterway as you can see it
> >> in
> >> the capture below :
> >>
> >> http://old.nabble.com/file/p30413623/skeleton5.jpg
> >>
> >>
> >> regards,
> >> Jérôme
> >> --
> >> View this message in context:
> >>
> http://old.nabble.com/Diagram-of-Vorono%C3%AF-to-Squelettisation-of-polygon-tp30413623p30413623.html
> >> Sent from the PostGIS - User mailing list archive at Nabble.com.
> >>
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> >
> >
> >
> > --
> > Georepublic UG & Georepublic Japan
> > eMail: daniel.kastl at georepublic.de
> > Web: http://georepublic.de
> >
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> Sent from the PostGIS - User mailing list archive at Nabble.com.
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-- 
Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.de
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