On 7/16/09, Chris Browet <[email protected]> wrote: > 2009/7/16 Matt Amos <[email protected]> > >> On Thu, Jul 16, 2009 at 10:41 AM, Chris Browet<[email protected]> wrote: >> > 2009/7/16 Frederik Ramm <[email protected]> >> >> Chris Browet wrote: >> >>> >> >>> I'd be curious to know how the api calculates the bounding box of >> >>> such >> a >> >>> relation >> >> >> >> >> >> >> http://wiki.openstreetmap.org/wiki/OSM_Protocol_Version_0.6#Bounding_box_computation >> >> >> >>> assuming the api definition is "the smallest bbox containg all >> >>> children bbox'es". >> >> >> >> It isn't. >> >> >> > >> > Ok. If I understand well, it adds to a relation bbox all the nodes and >> ways >> > of children relations (+ the "pure" ways and nodes, of course). >> > >> > That won't remove the problem of infinite recursion: R1 -> R2 -> R1; it >> will >> > add to R1 all ways/nodes of R2, which itself will add all ways/nodes of >> R1, >> > which will... >> > >> > Bottomline question is: How does the api handle the case? >> >> short answer: it doesn't. >> >> long answer: the position taken by the API for both map calls and >> changeset bboxes is that relations don't have physical extent - only >> their node and way members do. bboxes are calculated only from the >> immediate members of the relation, so recursion is necessary. >> >> > Err... I'm feeling thick, today... > > You are saying that the api IS recursing thru the children relations and > that the api also has an infinite loop problem, right? > OTOH, you saying "only from the immediate members", would mean it DOESN'T > recurse thru the relations?? (But it cannot be that or what would happen > with relations only comprising relations). > > Sorry for bothering about this, I'd just like to be sure on how to best > handle the case...
the second. it doesn't recurse through the relations. cheers, matt _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
