On Sat, May 21, 2011 at 10:18 AM, Stefan de Konink <[email protected]> wrote: > > Don't forget the binary format (PBF) also was basically twisted around > to accommodate for negative numbers. Your suggestion makes sense, there > shouldn't be negative IDs. And additional making the value NOT NULL in > the database, also gives one bit extra.
PBF has no problems with negative numbers. If there is, that would be a significant bug Software using PBF might have problems with negative ID numbers, but that's not the fault of the format. If you took an entire planet and negated ID numbers. There would be a a small hit to filesize because of negative ID's for ways&relations. About a 500mb/5% increase to the uncompressed file (~60 million way&relation entities, 2*4 bytes negative number overhead for the entity ID and, due to delta coding, the first member entity). With gzip compression, I'd expect <1% filesize hit.. When PBF first came out, osmosis had a few problems when PBF fed it (-1) as a user ID. Scott _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
