[OSM-talk] Id stability

Ture Pålsson ture at lysator.liu.se
Tue Aug 2 15:55:20 BST 2011


2011/8/2 Gregor Horvath <gregor at ediwo.com>:

> OSM provides uri's to ID's which are linked to names of
> physical objects. Example:
>
> http://www.openstreetmap.org/browse/node/1381574156

But these objects often make no sense in the real world!

In the real world, there are things like streets, pubs, counties and
hospitals, which have geometry (and other properties). In the OSM
database, in contrast, there are pieces of geometry, subdivided
according to topology into points (nodes), linestrings (ways), and
everything else (relations), which have "thingyness". The relation
between OSM objects and real-world objects is quite hairy and probably
depends on what sort of real-world object you are intrested in at the
moment (is a hospital a place to get yourself stitched back together
after falling of the bike while mapping, or a contender for "largest
building in a 5km radius from home"?).

I am beginning to suspect that the only sensible use for the OSM
database, is as input data to a processing step that converts it to
something more usable for a specific task. Using it "as is" is a
recipe for headaches.

I'm not saying this is a bad thing. The database is extremely flexible
and can accommodate almost any sort of geographic information one
cares to throw at it, it just takes some programming to use it!



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