Robin Paulson wrote: > this proposal has been languishing for 2+ months now, with little discussion > > http://wiki.openstreetmap.org/index.php/Proposed_features/Model%27s_Aerodrome > > please could i get some comments
I've posted comments there but I think that we need to get a higher level discussion under way on the hierarchy of the tagging system. And I'm not sure where to start it? Here or create a wiki page? I'll outline things here. There are two areas to be covered which are probably separate discussions but they dovetail together logically. Simply FINDING a tag is currently tedious and then knowing what to use with that tag becomes even more fun :( We have a number of top keys which I think need to be combined and layered to give a more logical progression. Going back to basics we have two types of element to manage a linear structure or an area ( a node is just a special case of an area, but even that may well have an area at a large enough scale ). The only difference between the two is that the line segments on an area must meet at the ends and while the M25 may be a circle, the area within it is different to the route itself. highway, waterway and railway are essentially 'way' type=xxx to which cycle, track, aerial can then be added. But rather than being too drastic, I think that three basic definitions can be applied to keep top level more manageable. highway - unconstrained route railway - constrained by track ( should be trackway but that will confuse ) waterway - constrained by water course Cycleway is just a type of highway Tracktype is just a secondary key for a number of highway types Aerialway is a type of railway There *IS* a case for simply combining all three, but apart from a few special cases the general rule is that vehicles do not move from one type to the other. I'll ignore amphibious cars, and the busway discussion identifies that only specially modified vehicles should move from highway to trackway. Airports are obviously a slight ambiguity since they have highways for taxiing and for taking off, but an airport should be a bounded area containing those features. I think this actually highlights the problem with the current structure where aeroway=aerodrome is defined for nodes when in fact it is an area? This is where the other discussion dovetails in ... All of the component parts of an airport 'is_in' the airport, but this is currently not managed properly. In the same way that country, county/state, town, locality and the like are not managed. We need as a matter of urgency to correctly manage the relationship between areas and the structures they contain. YES there are problems where an area straddles other areas, but that is just a special case that needs handling. If I search for all 'model_aerodrome' in the UK that is a reasonable request, but having to add 'is_in' to every tag is not the solution and needs to stopped now? Once we have the concept of area, landuse becomes obvious, and amenity in that area follows on? retail->shop ? cafe and the like leisure->sport ? even where professional activity the watching of is leisure military->military Obviously linear features like power lines, underground storm drains and the like need catering for but those type of features may just a special case? ( I'd still like to see numeric tagging with a multilingual title table even though I only speak English but that will come another day, for the moment we have to use English keys for the translation table :( - it would be nice if the translated versions of Map_Features had a column for the translated tag names! ) -- Lester Caine - G8HFL ----------------------------- Contact - http://home.lsces.co.uk/lsces/wiki/?page=contact L.S.Caine Electronic Services - http://home.lsces.co.uk MEDW - http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/ Firebird - http://www.firebirdsql.org/index.php _______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
