2009/6/4 Peter Miller <peter.mil...@itoworld.com>: > > 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,
You're assuming that's not a 20mph limit expressed in rounded down kph. > 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 Meh. 30mph == 48.28032 ~ 48.28 ~ 48 (and is what the highway code says). Any of those as tags will do for most purposes. The only one I'd complain about is specifying a mph value without the unit because it's impossible to determine what was intended. km/h is common enough to be used as the default. Whitespace is trivial to remove. FWIW highway code conversions are: 20mph = 32 30mph = 48 40mph = 64 50mph = 80 60mph = 96 70mph = 112 Dave _______________________________________________ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
