[OSM-talk] oneway=1

[Thomas Wood]

On 9/30/07, Arieh Skliarouk <skliarieh at gmail.com> wrote:
> Hello,
>
> I think it is wrong to specify street direction explicitly, at least
> for the long term. Street direction tend to change, and you don't want
> OSM users to get tickets for going wrong way?

They should pay attention to the roadsigns. Just because a map says it
is fine to do down a road doesn't mean that it is in reality.
http://news.bbc.co.uk/1/hi/wales/6959057.stm


> I am sure commercial mapping companies have some kind of agreement
> with authorities regarding directions change. Until OSM has something
> similar, we can't rely on this information to remain static.
>
> Direction tags on roads wider than certain width, can be relied upon,
> though. For narrow streets the direction needs to do deducted
> statistically.

I really don't think a road's direction changes that often if at all
in its lifetime. If so, it'll probably be part of a larger road
changing scheme in the area, someone will probably resurvey the area
if they are aware of it.

> I see following algorithm as one that can work:
>
> Initially, mark all narrow streets as having "questionable" direction,
> with allowed direction of the one that submitter have travelled on it.
>
> The client software (one that runs on PDA) needs to be able to notify
> server that the car just passed the street in previously
> known-forbidden direction. Once several similar-looking GPS-traces
> from different users are received by server, the street direction can
> be recalculated.

Some roads may have had traces taken by foot. Plus all data is
currently entered into OSM by hand, nothing is calculated
automatically from GPS traces at the moment.

> Similar way, server should deduct streets that have not seen certain
> direction GPS-traces and mark the street as "questionable" direction.
> PDA-client should notify the user about questionable status of the
> street direction and allow clarification of the data by user, with
> subsequent upload to the server.

This is a good idea, for any sort of data error or lack of data
flagged in the database.

> Other factors that can change in lifetime of a street (off the top of my head):
> * Whether only public transport is allowed
> * Trucks are allowed only during certain hours
> * Cars with dangerous cargo (explosives, fuel, etc) are not allowed
> * road is under (re)construction, find another route
> * Only certain maximum weight or height vehicles are allowed through
> * Pedestrian only
> * etc
>
> What do you think?
>
> --
> Arieh



-- 
Regards,
Thomas Wood
(Edgemaster)