[Talk-GB] maxspeed changes

[Peter Miller]

Good to have a proper discussion on the subject.

There does seem to be a a massive consensus around the world that maxspeed
should be used to hold a posted speed limit in km/h or mph as a numeric in
the local units. (this is based on current practice as indicated by ITO Map
and by taginfo). There is a smattering of countrycode:zone, but it is
small. The only major use is in Romania.

There seems to be a mood to use maxspeed:type for the supporting
countrycode:zone data here, although more people are using source:maxspeed
for this globally. I have continued to use maxspeed:type in my cleanup pass
because in a number of cases the source:maxspeed already contained
something like 'survey', 'sign at S end' or similar.

I suggest that we raise a proposal at some point to migrate the zone
information to maxspeed:type, but lets not worry about that for now.

What we can discuss here is how to tag the UK speed limits.

Based on the dilemma I have had numerous times in the past week to decide
is a slip-road or roundabout is technically a 60mph or 70mph I would
suggest that we produce some guidance on what value to use in various
situations (even though it is a bit irrelevant and nerdy for most
situations we could imagine). I tag slip roads at the dual carriageway
speed if at least one end is on a dual-carriageway. I tag roundabouts as
70mph if there are at least two dual-carriageways attached to them. I use
60 mph in other situations.

Given that it is not always 100% clear if a road is 'dual' or 'single', I
suggest that we simply use use a value 'UK:national' in maxspeed:type (or
in source:maxspeed). This would be in place of uk:motorway, uk:nsl_single
and uk:nsl_dual. To be clear, the tag should be uk:national not just
national given the strong guidance on the wiki and through usage that it is
appropriate to include a country-code prefix.

Fyi, I am very nearly done with my maxspeed cleanup. Only a few smaller
roads to go.

Keep up the good work.

I now realise that a simple way to capture a speed limit and its location
as a car passenger is to take a geocoded photo of the sign. It's sad how
long it has taken me to twig to that one!



Regards,


Peter

On 25 September 2012 20:49, Colin Smale <colin.smale at xs4all.nl> wrote:

> On 25/09/2012 18:25, Andrew M. Bishop wrote:
>
>> As the author of an OSM data consumer (the router "Routino")
>>
> Can I just say how refreshing it is to have some input from the data
> consumers. Most of the interminable debates about tagging are between
> parties who talk about data entry issues (how many clicks, how much support
> in editors etc) and could be sorted far more effectively by considering
> what people want/expect to get out of the data. If the consumers' point of
> view is not adequately represented OSM could easily degenerate into WOM
> (like ROM only it's write-only). Any attempt to limit mappers' creative
> freedom by "standardisation" is usually met with howls of derision and
> dogmatic refusal.
>
> Just my 2c...
>
> Colin
>
>
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