[Talk-GB] maxspeed field - what units should we use. etc

Andrew M. Bishop amb at gedanken.demon.co.uk
Thu Jun 4 17:27:26 BST 2009


Peter Miller <peter.miller at itoworld.com> writes:

> I have been looking at the coverage of maxspeed limit data for  
> highways in the UK and we seem to have a right mix of styles.
>
> Here is the data for bug chunk of England while avoiding including  
> anything from France or Ireland (which would include km/hour figure).  
> We current have over 17,000 highway ways tagged with maxspeed and also  
> 300 ways tagged as 'maxspeed:mph'. You will notice that for 30 miles  
> per hour we have 30, 30mph, 30 mph, 48.2, 48.28,  48.280, 48.27808,  
> 48.28032 and 48.28.
>
> Any suggestion on what we should recommend for the UK? I guess the USA  
> should also be party to this discussion but they have far less  
> population of the maxspeed field (only 70 uses in the Bay area) so  
> possibly we should come to a view first.  Our options seem to be:-
> maxspeed=30mph (the user should strip a trailing mph to find the value)
> maxspeed=30   (leaving it for the user to realise that it is in the UK  
> and therefore imperial)
> maxspeed=30 mph (the user should strip the last word if it is mph  
> including the space)
> maxspeed:mph=30 (Easy for the user)
> maxspeed=48.28 (with a defined precision) For metric use no work by  
> the user, for imperial use a look-up table is required or a conversion  
> and rounding

This question is already answered on the OSM wiki:

http://wiki.openstreetmap.org/wiki/Key:maxspeed

The answer is that maxspeed=30mph is the recommended answer if the
native units are mph.

-- 
Andrew.
----------------------------------------------------------------------
Andrew M. Bishop                             amb at gedanken.demon.co.uk
                                      http://www.gedanken.demon.co.uk/




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