Hi, I’ve recently been doing a fair bit of work mapping in the nooks and crannies of Portobello, Edinburgh. I’ve got a few questions rising out of that…
There is one area in particular which has a few main residential streets with the houses themselves in sort of courtyards clustered around very narrow streets. These streets are essentially the road, the footpath and the front gardens of the house. Typically there are two accesses, with a path then between those… If set as highway=residential they overpower the map at certain scale. Should they be service instead, or even living_street? See Law Place, Brickfield, The Pottery, New Tower Place and the others on http://www.openstreetmap.org/?lat=55.955291&lon=-3.115407&zoom=18&layers=B000FTF for the area in question and might be worth comparing a satellite image.
There’s conflicting documentation on what highway=unclassified really means. I’ve been assuming the hierarchy is: secondary, tertiary, unclassified, residential, service and that is consistent with http://wiki.openstreetmap.org/wiki/Key:highway but other pages seem to indicate unclassified as somewhat lower in the hierarchy than residential?
As for trunk roads vs primary - I understand the green sigs vs white distinction… But with that in mind the A1 in Edinburgh and the A199 to Leith are misclassified. I’m fairly certain no road inside the Bypass has green signs. For the A1 the green signs stop at Milton Link.
I treat unclassified and residential as pretty much equal, but one in residential areas and the other in more rural areas (there are a lot of lanes around here, and while some are quite useful shortcuts - which I may then class as tertiary - most I tag as unclassified). I believe some Potlatch users are unaware of highway=road and use highway=unclassified as one that still needs ‘classifying’ - which usually ends up with them classifying them later as tertiary for lack of anything else. There are areas near Colchester where every lane seems to be tertiary, for example.
I usually argue that if you think they should be residential then they probably are. If they’re much narrower than other residential roads add width or est_width tags and if they still look wrong on Mapnik/Osmarender (which as far as I know don’t yet use the width tags where they exist) then it will be a problem with their rendering and not with your tagging - file a bug report…
With regards trunk roads vs primary I thought the A133 was primary all the way from the slip road leaving the A120 (trunk) into Clacton, but someone retagged it. When I went and physically checked the signs I realised I’d not been paying attention having driven the road for years and drove the road all the way to the coast to check that it didn’t downgrade to primary at any point. If you are positive about them being primary rather than trunk then retag them - you’ll be correcting someone else’s mistake.