On Sun, Jun 15, 2008 at 08:53:53PM +0200, Frederik Ramm wrote: > Hi, > >> Do the "ways making up the route" (as defined on Relations/Routes >> proposal) must be actual highway-tagged ways > > Yes. > >> or they may be distinct >> (maybe untagged) ways drawn over the highway ways? > > To re-use a popular exclamation of the last few weeks: "Ye gawds no!" ;-)
Okay. :) > >> I am asking that because on some streets there may be many different bus >> routes going through it with different entry/exit points. If the ways >> making up the bus route must be the actual highway ways, those streets >> will need to be splitted on many tiny little ways, so that each section >> will belong to a different set of route relations. Did I understand it >> correctly? > > Yes. This is somewhat of a shortcoming but that's the way it is currently > done. This doesn't seem to be a problem only when making bus relations: streets with lots of tunnels or bridges need to be splitted also. So, it is a more general issue. I will try to live with it, by now. :) > [...] > > Or you simply ignore the fact that the bus route does not use the full > length of the way; it would still be possible algorithmically to find out > which part of the way the route uses (except from circular road layouts). > Won't look nice on today's renderers but who says they cannot be improved? That is an interesting idea: maybe I can do this to enter data about the bus routes more easily and later algorithmically split the ways on the right places. > > A third option would be inventing a special kind of relation that's called > a "way section"; it would contain the start node, end node, and way and > model that part of the way that lies between the two nodes. Then make your > bus route relation use these way sections as members wherever the bus route > doesn't use the full way. But this would also be something new and not yet > supported by renderers. I have seen two proposals that would handle the current cases of massive splitting: "tag section" relations (similar to what you mentioned above)[1] and "collected ways"[2]. Both seem to sove the same problem using different approaches. At first I thought the collected-ways approach to be better and more intuitive, but the way-section approach now seems to be better, the more I think about it. (The collected-ways proposal may be useful on other cases, but I was thinking about the cases of splitting due to bridges/tunnels and bus routes, only) [1] http://wiki.openstreetmap.org/index.php/Relations/Proposed/Segmented_Tag [2] http://wiki.openstreetmap.org/index.php/Relations/Proposed/Collected_Ways -- Eduardo _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
