It might be simpler than this. Assign_vertex_id only need to be called once for any given data set as this creates the data that a network is created from. Our wrapper routines then use the start and end to create a bounding box and then expand the bounding box to collect the sub-set of the total graph data that is needed to build a graph for a given solution.
So for the voronoi diagram, you could write a new wrapper function where you pass in two corners of a bounding box, that would then collect the graph data and build the graph for the Voronoi solver which would then return polygons of the solution.
-Steve
On 12/13/2010 10:18 PM, Daniel Kastl wrote:
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@aol.com <mailto:jrmrolland@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@aol.com <mailto:jrmrolland@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-Voronoï-to-Squelettisation-of-polygon-tp30413623p30413623.html
