Hello, Following from this conclusion (https://lists.openstreetmap.org/pipermail/tagging/2014-March/016904.html), I'm now trying to find a way to use tracktype, smoothness and surface to improve routing quality. For an average 4 passenger car (not an SUV, not a truck, not a motorcycle), I believe that:
1. Maximum "safe speed" is limited by how regular the surface is and also by how dense the surface material is. The exact material (in the "surface" tag) is not so important for routing as are these other two qualities (smoothness and material density). 2. Smoothness and surface density could be somewhat guessed from "surface" tag in most cases, and smoothness and tracktype could refine this guess. The exact "safe speed" for each value is probably a concern of each application, but for a guess of "expected smoothness" and "expected tracktype" (in the absence of these tags) in the absence of those tags, I need opinions. I think these associations make sense when the other tags are absent: [format: surface=smoothness,tracktype] asphalt=excellent,grade1 concrete=excellent,grade1 tartan=excellent,grade1 paved=good,grade1 paving_stones=good,grade1 concrete:plates=good,grade1 metal=good,grade1 compacted=intermediate,grade1 sett=intermediate,grade1 concrete:lanes=intermediate,grade1 bricks=intermediate,grade1 cement=intermediate,grade1 cobblestone=bad,grade1 wood=bad,grade1 stone=bad,grade1 rocky=bad,grade1 gravel=bad,grade2 fine_gravel=bad,grade2 grass_paver=intermediate,grade2 unpaved=bad,grade3 ground=bad,grade3 dirt=bad,grade3 grass=bad,grade3 pebblestone=bad,grade3 clay=bad,grade4 sand=bad,grade5 earth=bad,grade5 mud=very_bad,grade5 What do you think? I know each surface type can vary wildly, but I'm thinking of those situations in which people probably mean when they add a surface tag but not a smoothness or a tracktype tag. I'm not proposing these as defaults for tagging in OSM. I'm thinking about Emil Tin's idea (https://www.mail-archive.com/osrm-talk@openstreetmap.org/msg00389.html) of setting OSRM's speed according to surface as the minimum of several measures. I tried to multiply two factors as he suggests, but I was not satisfied with the resulting values. Then I tried to take the minimum of two speed values associated to smoothness and tracktype and it seemed much better. -- Fernando Trebien +55 (51) 9962-5409 "The speed of computer chips doubles every 18 months." (Moore's law) "The speed of software halves every 18 months." (Gates' law) _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
