Hi Mike, hi François, hi all, I don't find the "length=*" tag redundant either for linear objects like streetlines, especially in the case of pretty steep ones: as they're projected for mapping purposes from 3D to 2D, their actual length is not the one you measure on the map but you should consider dividing it by cosinus(A) where A is the angle of inclination between the local horizontal plan and the linear feature. Pythagore said it, man ;-) E.g.: a 17-degree mapped mountain road or San Francisco street's will get its actual length a 5% bonus compared to its real-life counterpart. Pick a 100-meter-or-more road, it's not just a bunch of cm. Depends on the accuracy you need, mostly for analysis purposes. http://en.wikipedia.org/wiki/Grade_%28slope%29 http://www.datapointed.net/visualizations/maps/san-francisco/streets-slope/ My 2c, - Yann
>>> [email protected]> 27/01/2015 16:15 >> ( mailto:[email protected]) Date: Tue, 27 Jan 2015 16:13:17 +0100 From: François Lacombe <[email protected]> To: "Tag discussion, strategy and related tools" <[email protected]> Subject: Re: [Tagging] length= Message-ID: <cag0ygldxgbc+oe2gloyzdhcg6qxjaozhcgzpbh9dh7snttd...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hi Mike, I don't find it redundant since the length=* tag can give the real length of a feature. The way in OSM is only a (sometimes not precise) drawing of an existing feature and can be different from the reality. The wiki can be completed with such a nuance. I personally recommend to use the length key while mapping street cabinets as nodes. http://wiki.openstreetmap.org/wiki/Tag:man_made%3Dstreet_cabinet All the best *François Lacombe* fl dot infosreseaux At gmail dot com www.infos-reseaux.com @InfosReseaux <http://www.twitter.com/InfosReseaux> 2015-01-27 16:04 GMT+01:00 Mike Thompson <[email protected]>: > I have noticed a "length" tag used on some linear ways [1]. It seems > that this is redundant, as the length could be calculated from the > geometry itself. It could also be the source of future errors should > someone split the way, for example to add more detailed tagging, such > as varying smoothness. > > The length key does have a wiki page [2], but the page doesn't have > much content. Perhaps it is only intended for nodes? > > What do you think? Should the length tag be used with ways and > relations where the length can be calculated from the geometry itself? > Am I missing something? > > MIke > > [1] https://www.openstreetmap.org/way/324078614 > [2] http://wiki.openstreetmap.org/wiki/Key:length >
_______________________________________________ Tagging mailing list [email protected] https://lists.openstreetmap.org/listinfo/tagging
