[pgrouting-users] Question about driving_distance calculation

Daniel Kastl daniel at georepublic.de
Wed Jan 12 09:27:07 EST 2011

2011/1/12 Markus Innerebner <markus.innerebner at inf.unibz.it>

> Daniel Kastl wrote:
>>>   ok, thanks
>>> The algorithm uses only the cost column(or reverse_cost column) of the
>>> edges to compute the costs of the target vertex? This means there is no
>>> way
>>> to compute the cost in dependency of a passed walking speed parameter,
>>> where
>>> cost are defined as edge_length/speed.
>>>  The cost is what you define as cost. Anything is OK. You select the cost
>> column in your query, which can be a combination of several attributes.
> ok, perfect.
> My last question now:
> the function returns a edge_id, described by the identifier of the edge
> crossed. What is the benefit of this attribute? What does this edge do?
> If the result contains the vertices reached in the given time from the
> query point, why also adding the edge identifier?

Nothing ;-) ... it doesn't do anything as far as I remember. (or please
correct me, Anton)
It's possible to discuss whether this is a good idea or not, but the reason
is that the query result is in the same form as the core shortest path
functions. You don't need to select everything ("*").


> Markus
> _______________________________________________
> Pgrouting-users mailing list
> Pgrouting-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/pgrouting-users

Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.de
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/pgrouting-users/attachments/20110112/cdd07298/attachment.html

More information about the Pgrouting-users mailing list