[OSM-talk] Extracting a BBOX from an osm change file

[Matthias Julius]

Phil! Gold <phil_g at pobox.com> writes:

> * Rodolphe Quiedeville <rodolphe at quiedeville.org> [2011-03-11 13:39 +0100]:
>> I want to know if changes files from
>> planet.openstreetmap.org/hourly-replicate/ are useful for a BBOX. My
>> first idea wass to to this with osmosis, if someone give me a hint.
>
> You can't apply a bbox to a change file.  Change files basically contain
> the IDs of changed objects and their current properties.  Notably, they do
> not contain the old properties of the objects, so osmosis cannot tell in
> all cases whether an object should be considered to be in or out of the
> bbox.

To be a bit more precise: Change files contain only changed objects but
not their dependencies.  That means that if someone changes a tag on a
way or relation the change file will contain that way or relation but
not the nodes they contain.  Therefore, osmosis can not know where that
way or relation is located.

Matthias