"Tristan Scott" <[EMAIL PROTECTED]> writes: > If this catches on not only do we have a well-defined and easily-processed > value for > "speed" to use in all manner of things, we also have a template for defining > other > data types (bridge height? maxweight?) which might (or might not) make the > job of > the data processor for an map consuming application (satnav etc) much easier. > > Tristan > > 2008/10/14 David Earl <[EMAIL PROTECTED]> > > On 14/10/2008 18:26, Tristan Scott wrote: > > Given that SI units are standard across OSM could be define a "speed" > value > in addition to "Numeric" "String" etc like so: > (default to kmh as specified before (also means not adding millions of > pointless "kmh" strings to the db) > Factor means "multiply by this to convert to SI - interpreters would > either > use value as-is or multiply by Factor for that suffix to get SI units. > "Suffix" is the entire string after the numerical value, with > whitespace > trimmed - so spaced/not spaced suffix wouldn't matter - defining this > rigidly would be ignored by most users, i suspect > > My proposed table: > Unit - Factor > "" - 1 > "kmh" - 1 > "mph" - 1.609 > "knots" - 1.852 > > +1. > > I really don't see what all the fuss is about. It's not exactly novel to > do it > this way: CSS puts units as part of the value. > > It's what I've been doing all along, except some pedant comes along and > changes > it to some incomprehensible decimal number almost as soon as I add them > to the > map (which means I can carry on doing it that way even if others think > differently, as they'll get converted automatically as far as i am > concerned and > I don't have to think about a magic number in km/h).
Earlier tonight I patched not-in-map_features.pl to accept units for maxspeed, se the post to the tilesathome list for all the details. I think this proves a point: If it's doable to parse it in perl-generated xpath in under an hour it's not really hard to code. Don't ask me to add support for validating maxspeed:mph etc, to check that it doesn't conflict with other units or anything, I wouldn't know how to start doing it... What about making some new lists on the wiki detailing units, make it at least as machine-readable as map features (preferably a little more, as parsing map features is a mess) and I could have the maplint test automatically fetch it's unit descriptions there. This would also make it easily documented, the value column in map features would say "speed" which links to a page explaining the units allowable for this data type. Exactly how to fit this in with the current template magick in map features is left as an exercise for somebody well versed in mediawiki voodoo. -- Knut Arne Bjørndal aka Bob Kåre [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk
