Hi, Not wanting to change current consensus in Belgium, but I wonder how close this would be to current mapping practice in Belgium, and if it would be a way of thinking that could help in some current edge cases.
---------- Forwarded message ---------- From: Fernando Trebien <fernando.treb...@gmail.com> Date: 2018-02-15 19:14 GMT+01:00 Subject: Re: [OSM-talk] Highway=trunk : harmonization between countries ? To: t...@openstreetmap.org Landing on this discussion several months late. I've just heard of it by reading a wiki talk page . Since 13 February 2009, the wiki  criticises highway classification as problematic/unverifiable. This has also been subject to a lot of controversy (and edit wars) in my local community (Brazil), especially regarding the effect of (lack of) pavement. In trying to achieve greater consensus some years ago, I decided to seek opinions elsewhere and finally I arrived at this scheme  which I think is very useful, if not perfect yet. It can be easily summarised like this: - trunk: best routes between large/important cities - primary: best routes between cities and above - secondary: best routes between towns/suburbs and above - tertiary: best routes between villages/neighbourhoods and above - unclassified: best routes between other place=* and above For example, the best route between two villages would be at least tertiary. So would be the best route between a village and a town or a city. Parts of this route might have a higher class in case they are part of a route between more important places. It surely raises the problem of determining optimal routes. Maybe a sensible criterion would be average travel time without traffic congestion. A number of vehicles may be selected for this average - could be motorcycle+car+bus+truck, or simply car+truck. Early results in my area [4, in Portuguese] seem promising and have produced more consensus than any previous proposals. To me, this method seems to: - resist alternations in classification along the same road - work across borders (where classification discontinuities are expected because each country is using different classification criteria) - account for road network topology - work in countries with mostly precarious/unpaved roads or without/unknown official highway classes - work between settlements as well as within settlements Borderline cases are probably inescapable in any system that does not use solely criteria that are directly verifiable - from the ground, or from the law. Maybe, in certain developed countries, the system is so well organized that merely checking signs/laws is sufficient. That does not mean it is like that everywhere on the planet. OSM has so far received a lot of input from communities in developed countries (mostly Europe, North America and Australia) and hasn't given much attention to less developed/organized countries. What comes closest to this is what the HOT Team does, but the judgment of road classification one can do from satellite images in a foreign country is much more limited than the criteria that have been raised in this thread so far. I wouldn't endorse tags such as maxspeed:practical due to lack of verifiability (it should be obvious that different types of vehicles would achieve different practical speeds). It is better to use the legal speed in maxspeed=* and describe the practical reason for a lower speed using surface=*, smoothness=*, and, who knows, maybe the not yet approved hazard=*  (though that is intended for signed hazards, not subjective/opinionated hazards). For the sake of long-term sanity, I also wouldn't mix the purpose of one tag with the purpose of other tags. To describe the surface, there is surface=*, smoothness=* and tracktype=*. To describe access rights, there is access=*, foot=*, bicycle=*, motor_vehicle=*, etc. To describe legal speed, maxspeed=*. To describe curves, there's geometry. Purpose, perhaps, is the main issue. What is the purpose of highway classification? Is it to save us the work of adding extra tags? Is it to allow the renderer to produce a cleaner output at low zoom levels? Is it to allow routers to assume default speeds? Maybe to guide their routing heuristics? Is it to express some sort of importance? If so, by which perspective - urbanistic, traffic engineering, movement, commercial value, cultural/fame, historic, some combination of those? Should the purpose be the same in every country? It may be interesting to also discuss the classification adopted by other maps. I don't have a reference for Google (originally TeleAtlas) or Here.com (originally Navteq), but Waze publishes its per-country road classification criteria in its wiki. [6-16]  https://wiki.openstreetmap.org/wiki/Talk:Tag:highway% 3Dtrunk#change_.22high_performance.22_to_.22high_importance.22  https://wiki.openstreetmap.org/wiki/Verifiability#Problematic_tags  https://wiki.openstreetmap.org/wiki/User:Ftrebien/Drafts/ Generic_highway_classification_principles#Schematic_diagram_and_general_ comments  https://forum.openstreetmap.org/viewtopic.php?pid=674296#p674296  https://wiki.openstreetmap.org/wiki/Proposed_features/hazard  https://wazeopedia.waze.com/wiki/USA/Road_types  https://wazeopedia.waze.com/wiki/UnitedKingdom/Roads#Road_types  https://wazeopedia.waze.com/wiki/Canada/Main_Page#Road_Types  https://wazeopedia.waze.com/wiki/Commons/Road_Types/India  https://wazeopedia.waze.com/wiki/Brazil/Como_categorizar_e_nomear_vias  https://wazeopedia.waze.com/wiki/Germany/Kartenlegende_(Deutschland)  https://wazeopedia.waze.com/wiki/France/Classification_France  https://wazeopedia.waze.com/wiki/Italy/Tipologia_delle_strade  https://wazeopedia.waze.com/wiki/Indonesia/Panduan_Tipe_Jalan  https://wiki.waze.com/wiki/%E9%81%93%E8%B7%AF%E7%B1%BB%E5%9E%8B  https://wiki.waze.com/wiki/%E3%80%8C%E9%81%93%E8%B7%AF%E7% A8%AE%E5%88%A5%E3%80%8D -- Fernando Trebien +55 (51) 99962-5409 "Nullius in verba." _______________________________________________ talk mailing list t...@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk -- Joost Schouppe OpenStreetMap <http://www.openstreetmap.org/user/joost%20schouppe/> | Twitter <https://twitter.com/joostjakob> | LinkedIn <https://www.linkedin.com/pub/joost-schouppe/48/939/603> | Meetup <http://www.meetup.com/OpenStreetMap-Belgium/members/97979802/>
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