[OSM-dev] Planet dump updates to include relations as an extra file

Dirk-Lüder Kreie osm-list at deelkar.net
Sun Apr 13 20:32:00 BST 2008


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Andy Allan schrieb:
| Jon,
|
| Given that #relations < #ways < #nodes, and you (generally) need to
| know about all the relations before you process the ways, and you need
| to know which ways you are interested in before deciding which nodes
| to keep - would it not make sense to dump the relations into the file
| first, followed by the ways, then the nodes last?
|
| Albeit I'm only thinking of osm2pgsql, maybe there's other things that
| wouldn't work this way round.
|
The obvious solution to me would be to abandon the monolithic planet
file altogether or at least provide separate files for nodes and ways,
too. programs optimized for planet file consumption (in the known order)
would then keep using the monolithic file, while other applications
could freely use the separate files.

.oO(The only thing I can see with using the "nodes first" approach is,
that it might easier to cut bboxes from the file, since the nodes are
the objects carrying the georaphical positions.
IIRC it is possible to simply concatenate bzip2 files to get one large
file that will, upon decompression, result in the uncompressed files
concatenated. Then you only have to deal with stuff like where to put
the <osm> tags in the separate files. (or you would need to filter them
on applications consuming this sort of data)...)

- --
Dirk-Lüder "Deelkar" Kreie
Bremen - 53.0952°N 8.8652°E

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