2010/1/2 Graham Jones <[email protected]>: > I think I have found the problem - I was using planet_osm_nodes lat and lon > fields. If I use the planet_osm_point way field, and extract the > coordinates using ST_X() and ST_Y() all of the numbers match up. > > You can see the factor of 100 difference if you do: > select id,lat,lon,astext(way) from planet_osm_nodes, planet_osm_point > where id=osm_id and id=27496146; > > This gives: > mapnik=# select id,lon,lat,astext(way) from planet_osm_nodes, > planet_osm_point where id=osm_id and id=27496146; > id | lon | lat | > astext > > ----------+-----------+-----------+------------------------------------------- > 27496146 | -13446488 | 730126793 | POINT(-134464.883471724 > 7301267.93936479) > (1 row) > > mapnik=# > > Is this a bug in osm2pgsql, or a 'feature'? Does anything use the lat/lon > fields?
The factor of 100 is a feature and is setup at [1]. It allows osm2pgsql to store the position as a fixed point 32 it integer taking just 4 bytes, instead of the 8 bytes required for a double precision floating point value. osm2pgsql uses the lat/lon fields when looking up the node locations. 1: http://trac.openstreetmap.org/browser/applications/utils/export/osm2pgsql/middle-pgsql.c#L27 -- Jon _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
