[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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