This is a question pertaining to osm2pgsql, osm2pgrouting and nominatim. As I understand it, these are 'lossy' methods for getting data from OSM and into a PostGIS database. I was wondering:
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asked 30 May '13, 15:31 FortyLashes Frederik Ramm ♦ |
Yes, these are lossy methods. For example, osm2pgsql drops coastlines, and the main outputs manipulate data into OGC simple features, which loses information regarding routing relationships. You can load osm data into postgres in a lossless fashion using osmosis and the --write-apidb or --write-pgsql outputs, depending on what schema you wish to use. answered 30 May '13, 19:12 Andy Allan @Andy Allan Sorry for not getting back sooner! Thank you for that! I have been looking into Osmosis - that is awesome you can do lossless!
(14 Jun '13, 18:06)
FortyLashes
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I assume that by "OSM data" you mean the OSM source data and by "lossy method" you mean that the output dataset, after processing it by a "method", contains at least one less (missing) or changed object compared to the input dataset. If these assumptions are correct my answers to your questions are: answered 31 May '13, 08:12 sanser |
The most common lossless DB schemas are apidb, pgsnapshot, pgsimple and OSM3S. apidb
pgsnapshot
pgsimple is pgsnapshot with separate tables for tags instead of hstore OSM3S
None of them are well-suited for rendering. The main uses for these database types are analysis and when you want to be able to produce a .osm file for an area. answered 14 Jun '13, 20:02 pnorman |