Hi, I have some questions about the osm2pgsql and it's output to the tables <<osm>>_line, <<osm>>_polygon and <<osm>>_rels (hereby called tables line, polygon and rels).
After loading OSM data there are three remarkable things in the resulting tables regarding osm_ids: 1. In the tables lines and polygons there exist rows with negative osm_ids. 2. Tables lines and polygons contain rows with duplicate osm_ids and identical attributes except geometry. I'd explain the first observation (negative osm_ids) by the following: The original (positive) id comes from a relation including its tags. So, given e.g. a multi-line or a multi-polygon relation which referrs to two ways it's clear that there is one (relation) id split into two rows in line/polygon table with the same (now negative) osm_id and with different geometries each. Table polygon has duplicate osm_ids like lines table but only with negative ones. But lines table also contains positive osm_ids! => Why this duplicate positive osm_ids in lines? In original OSM database there is no relation and only one way id (see e.g. http://www.openstreetmap.org/browse/way/47926394 and compared this to "select id, tags, length(way) from osm_line where id=47926394" which will return three rows). 3. Then in table <<osm>>_rels which I don't understand following attributes: * way_off (smallint) * rel_off (smallint) * pending (boolean) -- exists also in table osm_ways * parts (integer[]) * members (text[]) => Any hints? Yours - S. _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
