Hi Jochen, Could you please comment on this thread: http://lists.openstreetmap.org/pipermail/talk/2009-July/039217.html http://lists.openstreetmap.org/pipermail/talk/2009-July/039259.html http://lists.openstreetmap.org/pipermail/talk/2009-August/039847.html
since you created the 'T-junction' rule in the first place back in feb 2007: http://wiki.openstreetmap.org/index.php?title=Key:tunnel&diff=next&oldid=23441 As you are the co-author on a book on tagging I feel I should ask your input on this :). On Tuesday 11 August 2009 15:31:24 Lambert Carsten wrote: > On Saturday 08 August 2009 14:11:21 Marc Schütz wrote: > > > > no, it's not, it's about relative order in the db. > > > > > > Fair enough. In other words, at any node which is a junction of way > > > segments with different layers (whether the segments are part of the > > > same way or different ways), the physical implication is that the > > > slope of the way changes in the close vicinity of that node. > > > > Not even that: it only says something about the relative ordering, not > > about slope. > > > > Regards, Marc > > Here is just one of the many examples in Amsterdam concerning bridges: > > http://maps.google.com/maps?f=q&source=s_q&hl=de&geocode=&q=bayreuth&sll=37 >.0625,-95.677068&sspn=59.467068,107.138672&ie=UTF8&t=k&ll=52.371356,4.897274 >&spn=0.001132,0.003447&z=19 > > All the connecting roads are more or less on the same physical 'layer'. The > roads that do not intersect with anything on another level don't have a > layer tag and are assumed layer=0. (A layer tag only has meaning relative > to something that is intersected). > Clearly the bridge starts at the (in this case 'X') junction. All the > connecting roads are (implied) layer=0. > The T-junction rule makes it necessary to add a non existing 'segment' OR > add three (for this bridge actually 6) layer=1 tags. Of course the other > end of those ways will connect to other roads. So the T-junction eastwards > will also need layer=1 tags which in turn will force the X intersection > northwards to have layer=1 tags. The result is of course that most or all > of the roads will need a layer tag. And where we finally connect Amsterdam > to the rest of Holland we have to hope that there are enough I connections > so we don't endup forcing the whole world to sit on layer=1. > The 'segment adding solution' does not only not represent the reality. > Those extra bits have hardly any room because it has to fit between the > junction and the 'natural=water' to work. > > All the layer tag does is make it clear that a crossing of ways do NOT > connect/intersect and the numbering helps the renderer to make a decent > representation on a 2D drawing. It is not about slope or height and > shouldn't be. > > >I think we should insert a "in most cases" into this rule. > > What is the point of this? > > O.K. if I delete the 'offending' :) bits in the wiki? > http://wiki.openstreetmap.org/wiki/Key:tunnel#How_to_Map > http://wiki.openstreetmap.org/wiki/Key:bridge#How_to_Map Also here (since july 2009): http://wiki.openstreetmap.org/wiki/Editing_Standards_and_Conventions#Bridges Lambert Carsten _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
