[OSM-newbies] Maxspeed

[Thomas Meller]

Now that the 'un-word' has been written:

'assumption'

Being explicit adds some ambiguity.
OSM seems to have no means to define local defaults to be used.
Ideally, there would be a bounding area defining the defaults and containing the ways on which the defaults are valid.
Or else, there would be need for a relation defining defaults.

There ist no API function for such a thing.
So being explicit solves the problem, or so it seems.

In the US, it might be true that defaults exist, but that's not the case in Europe.

That leads mappers to map things which aren't there.

For example, in most countries riding a bicycle is forbidden on footways per default. So people map a path, think it is a footway, and tag 'bicycle=no'.
But there is no traffic sign at all.

So what's true?

It depends on who interprets the map data. And because there is no agreed standard, interpretation is a question of personal taste and leads to errors, depending in which area which mapper did his work.

I think it is desirable to find a solution and to not map anything which is not explicitly named in reality. There is need to find a solution for this issue.

I personally think it is best to draw a bounding box of some kind (landuse=residential) and wait for a function to be added.
Or you can take the effort to map it now and undo your work everywhere where there are no traffic signs in the future, when such a function comes to existence.

Your choice.

-------- Original-Nachricht --------
> Datum: Mon, 08 Mar 2010 20:08:29 +0000
> Von: "Seventy 7" <seventy7 at operamail.com>
> An: newbies at openstreetmap.org
> Betreff: Re: [OSM-newbies] Maxspeed

>  Ideally you would be explicit, but personally I don't tag every single
> way with a maxspeed (or lanes or smoothness or surface or width ...).
> As for routing, an assumption that highway=residential is 30 unless it
> says otherwise and everything else is 60 unless it says otherwise (or is
> a motorway/dual carriageway) would probably work ok.
> 
>   ----- Original Message -----
>   From: "Steve Bennett"
>   To: newbies at openstreetmap.org
>   Subject: Re: [OSM-newbies] Maxspeed
>   Date: Mon, 8 Mar 2010 21:06:53 +1100
> 
> 
>    On Mon, Mar 8, 2010 at 1:14 AM, Seventy7  wrote:
>   > I wouldn't do it this way. I would leave maxspeed off all the roads
>   tagged
>   > highway=residential and only tag the ones other than these, i.e.
>   the
>   > small section of the approach roads where they pass the boundary?
> 
>   I think because of the way OSM works that it's usually better to be
>   explicit. A road with "maxspeed=50" has a clear meaning. A road
>   without a maxspeed could mean that there is no limit, that the limit
>   is defined by some local rule, that it simply hasn't been mapped, etc
>   etc.
> 
>   Steve
> 
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