[pgrouting-users] Question about driving_distance calculation

[Markus Innerebner]

Hello Daniel

thanks for your detailed answers.
> 
> Driving Distance functions starts with a vertex. (There is a wrapper
> function that takes coordinates as start and searches for the nearest vertex
> from the given point).
> 
> 
> 
>> 2) what happens with edges, that are partially reached? (one vertex is
>> reached in time, the other one is not)
>>
> 
> Driving Distance only cares about vertices, because it works like Dijkstra
> algorithm. You can take the vertices and write an SQL function for example,
> that returns you the edges ... or a polygon.
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.


regards

Markus