Hi All, I'm have a similar question to Mark's. The words "trunk", "primary", "secondary" and "tertiary" implies a functional classification. A functionally classified road network should have each class (more-or-less) forming a closed network. The "motorway" class is not a functional classification, but a physical classification. For me, using the "motorway" class is acceptable because that is the way street maps are typically made: showing dual carriageways as the top class regardless of route designation or function. Anyway, only rarely in the case of underutilized dual carriageway roads is that an incorrect assumption.
Defining "trunk" as N roads is making it a network classification. Since trunk roads are rendered in green and we want to see the national network on the map, regardless of function, it works. We have (at least) 3 different ways of classifying roads and these need to be blended into one classification. Our problem is also that we have to use the existing classes and get the OSM map to look like the street maps we are used to in SA. (In terms of colouring & the scales at which they display). The "tertiary" class is not mentioned on the tagging standards page. Yet there are a lot of them, many which (like trunk) "looks" right. My suggestion is to define the tag names as follows: Any freeway = "motorway" (physical classification) N roads (undivided) = "trunk" (network classification) Major routes linking into freeways and N routes, typically low numbered M & R = "primary" (main roads: combination between functional and network classification) Important routes linking into "primary" (main) roads (this sometimes will be a road without a R designation) or routes linking up populated places = "secondary" (network classification) Local collector roads, ie. residential roads that carry through traffic (often residential roads with sidewalks) = "tertiary" (functional classification) The rest = either "residential" or "unclassified". In terms of the correct naming of the above (for legends on customized maps) I would go for: Freeways National roads Main roads Secondary roads Collector roads Residential / other My suggestion for "tertiary" will invalidate many of the current "tertiary" roads - those that are not residential and are connecting populated places. A good example is the R104: Pretoria street connecting Bronkhorstspruit parallel with the N4. http://www.openstreetmap.org/?lat=-25.7542&lon=28.4227&zoom=13&layers=B000FTF Comments? Regards, Paul. _______________________________________________ Talk-ZA mailing list Talk-ZA@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-za
