On Tue, 18 Apr 2023 17:08:39 +0200, Marc_marc <marc_m...@mailo.com> wrote: > Le 18.04.23 à 16:53, Mateusz Konieczny via Tagging a écrit : >> Is tagging of fuel: assumed to be exhaustive? > > no, some contributors will fill in what they are interested in, > others will fill in everything that is visible (and may not > be able to see the blue additive pump not visible from the car pumps), > others will do an exaustive survey
Agreed. IMHO basically the main reason why multi-tag standard (e.g. fuel:octane_98=yes, fuel:diesel=yes, fuel:lpg=no) was invented is precisely because in multi-value system it would have been impossible to mark the difference between "this fuel is not present" and "it is unknown/unsurveyed if this fuel is present here", i.e. it would make a pressure on mapper to either: - invest a lot of time to map EVERYTHING, or - better map NOTHING if they didn't have that time (in order not to create more confusion / false data) e.g. if "fuel=octane_98;diesel" was tagged, it would be ambiguous - does it mean that there there is no LPG, or that the mapper didn't care to survey that separated area of fuel station where LPG is being held? With multi-tag standard it is unambiguous, and users may map as much or as little as they want, and other people can iteratively improve later according to their preferences. E.g. if I just tanked diesel into my HGV on some fuel station, I can add tag "fuel:HGV_diesel=yes" and go on my way (or mark "fuel:HGV_diesel=no" if I see that this fuel station is useless for me), knowing that next time I need it the map would be more useful to me and other HGV drivers, and *without* having to take a walk and map every other type of fuel available to regular car drivers (unless I want to and have time to kill)... So, if it is tagged "fuel:lpg=no", it means there is no LPG there, if it is tagged "fuel:lpg=yes" it means there is LPG there, and if "fuel:lpg=*" is missing completely, it means it is (currently) unsurveyed (and should be surveyed if one cares about LPG availability). As a sidenote, another (much less important in practice, but potentially problematic as number of values grew) advantage of multi-tag standard was that the limit of max. 255 chars per tag is avoided) -- Opinions above are GNU-copylefted. _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
