[OSM-talk] Are osm ids unique?

D Tucny d at tucny.com
Wed Jan 14 07:11:19 GMT 2009

2009/1/14 Nop <ekkehart at gmx.de>

> Hello!
> Are the ids of osm objects unique?
> A) globally unique
> B) unique only within the type of object, so the same id may occur with
> a way, a node and a relation.
> C) unique only within the type of object, but with non-intersecting
> numbering schemes
> According to the wiki it is B) [1]
> In my data processing I have so far assumed A) and never encountered a
> problem.
> What are the facts?

B is the case...


You may not have encountered a problem with assuming A in a limited dataset
as the 'current' value for ways is significantly smaller than for nodes and
the current value for relations is significantly smaller than for ways due
to there being a lot more ways than relations and a lot more nodes than
>From http://www.openstreetmap.org/stats/data_stats.html:
Number of nodes296115165 Number of ways24186209 Number of relations53679
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