[pgrouting-dev] driving_distance Synopsis

[Mario Basa]

Hello Steve,

I wrote the initial code for the driving_distance, although Anton modified
it quite a bit afterwards.

Basically it uses a slightly modified Dijkstra that traverses the graph
from a starting point while measuring the lenght/time along the way. After
a set length/time has been reached, *all* the nodes (along with the x,y
coordinates) are passed to CGAL to get the outer points and create a
concave hull polygon.

The bottleneck here is in the passing of the nodes since in a dense graph,
the data can be quite large. Anton and I were trying all sorts of ways to
filter first the nodes, but couldn't find an efficient method without
loosing accuracy.

Regards,

Mario.


On Wed, Mar 7, 2012 at 9:36 AM, Steve Horn <steve at stevehorn.cc> wrote:

> Hello list.
>
> I am interested in digging in more to the driving_distance functions to do
> some refining and perhaps improve the usefulness of the results (
> http://lists.osgeo.org/pipermail/pgrouting-dev/2012-February/000458.html).
>
> Having a hard time deciphering the current implementation, mostly because
> of my lack of familiarity with c/c++. Is there someone who wouldn't mind
> giving a synopsis of the overall approach that the algorithm takes?
>
> Thanks!
>
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>
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