[OSM-newbies] Maxspeed

[Pieren]

not sure if this list is appropriate but tell us if we have to move out

On Tue, Mar 9, 2010 at 6:12 PM, Thomas Meller <thomas.meller at gmx.net> wrote:


> There is no debate which way gets which maxspeed tag.
> There is an ambiguity which way is which type.
>
> Is a path per default a footway or is it a cycleway? When there is no
> explicit tag, which decision is right?



Tag a footway "highway=footway" and a cycleway "highway=cycleway". If it is
multi-usage, tag it "path" and consider "bicycle=yes" and "foot=yes" if
nothing else is mentionned.


> In Switzerland it may happen that a primary route crosses a town.
> That does not mean that a speed limit other than the default for primary
> routes is valid. There _has_ to be a traffic sign.
>

This is another discussion which is unclear today : where is the limit
between urban zones and countryside (the "inside place" vs "outside place"
on the wiki). Some people consider that the landuse=residential polygon
could be enough. Others would like to use the "traffic_sign=city_limit".


>
> Different countries, differing rules.
> We need to get a standard way to address this.
>
>
We try but sometimes, we have to accept that the rules are country specific.
For instance, "highway=cycleway" is quite clear in Europe, but not in
Australia. And even inside Europe, "foot=yes" is implicit for cycleway in
some countries but is "foot=no" in some others. Does that mean that what is
obvious for local mappers (foot=yes/no) has to be fulfilled just because it
is not worldwide standardized ?


> And a routing algorithm could take into account that a primary road
> crossing a town cannot be used driving at maxspeed.
>

Routing applications will have to preprocess the data and make assumptions
anyway. If you wait until all highways carry a maxspeed tag populated by
humans or editors presets, you will never end up.


>
> Think of a hiking path that crosses a country border. Think of the rider of
> a mountainbike. Which access restriction is in effect? Where does the
> situation change? Will every mapper be foresightetd enough to explicitly tag
> the way correctly? Exactly at the border?
>
>
Not sure I'm following you here. You said yourself "Ideally, there would be
a bounding area defining the defaults and containing the ways on which the
defaults are valid.". Any geographic application should be able to determin
if an element is inside the bouding area or not. This bounding area is
already defined for many countries in OSM.

 The case of a residential road is easy for us Euopeans. Have a look on the
> US defaults. They change at the state borders. Whether that has a meaning or
> not I cannot tell. Depends on the local situation, I think.
>
> Thomas
>
>
Yes, ok. It's not more complicated than between Switzerland and
Liechtenstein. The default values are documented in wiki pages : just
enhance the list of bounding areas from the countries to the states when it
is required. What is the best : adding a subset of default values for 50
states and improve the wiki if we have ambiguities  or asking people to add
maxspeed tag in millions highways ?

Pieren
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