[OSM-talk] zones for motorway/in town/outof town?

[Guenther Meyer]

Am Wednesday 20 May 2009 schrieb Radomir Cernoch:
> Hi,
>
> I would like to ask about the proposed feature 'trafficzone'. If I
> understand it right, it proposes to add a tag to _every_ highway and
> _every_ road in the city. I'm afraid that this solution is highly
> redundant in the amount of information and therefore it's likely that
> someone will forgot to add the right tag.
>
yes, this may be redundant, but I think it's the easiest way to tag and use 
these values.
the other possibilities would be creating a polygon or a relation, but this 
seems to be rather complex to map and to use...

> In the Czech list we ended up with the following solution, which tries
> to copy the legislation (which is a good starting point, I guess):
>
right.

> 1) Every road is by default 'rural' road (speed limit 90 km/h).
> 2) Every highway has speed limit 130 km/h by default.
> 3) If a road is inside a polygon tagging the city limits,
>    then its speed limit is set to 50 km/h. Such polygon might be tagged
>    by 'place', but the actual name of the tag is not important here.
> 4) If a road has different speed limit from rules 1) - 3), it is tagged
>    with 'maxspeed=...'.
>
sounds reasonable...

> By this scheme it's easy to set the speed limits right very quickly on
> most roads, because it only requires to add the polygon with 'place' tag
> (or any other name we agree on). At the same time you can set the speed
> limits as detailed as you want to.
>
...but you would need some kind of gis database/functions to evaluate the 
polygon data.
the easy way of reading just keys and values like with most of the other 
features in the osm database would not be possible.




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