[OSM-talk] Relations not always brilliant

[Sven Grüner]

Sebastian Spaeth schrieb:
> You do know that sometimes people need to download all entities of a
> relation when they download an area with a single node in it? I wouldn't
> want to download all elements of "earth" when I download my
> neighbourhood block. :-) How do you handle this problem?

Well, currently the API only returns direct members, so do our editors 
as well as my script. For "Earth" that would only be the few continents 
and a couple of oceans, totally bearable.

When you start to put all Autobahnen in the Germany-relation (since they 
are run and owned by the national governemnt) you will obviously run 
into trouble just when downloading direct members.
But this could be solved by only making the way-relation as proposed in:
http://wiki.openstreetmap.org/index.php/Relations/Proposed/Collected_Ways

That would result in about 100-200 direct members (instead of thousands 
of ways with millions of nodes), which is okay again. Alternatively one 
could request special member-groups of a relation by their role. I.e. 
"give me all states of Germany and the capital but not the Autobahnen, 
national buildings, etc."

This is of course still an issue but I believe that solutions will occur 
shortly after we run into serious trouble like always in OSM. And it 
will be a while till relations are so well used to cause  bandwith-problems.

regards, Sven