[OSM-talk] osm2pgsql and proper/legacy mercator

[Jon Burgess]

On Fri, 2009-05-01 at 17:52 +0200, Francois Van Der Biest wrote:
> Hi list,
> 
> osm2pgsql --help says:
> -m|--merc: Store data in proper spherical mercator (default)
> -M|--oldmerc: Store data in the legacy OSM mercator format
> 
> I'm wondering what's the difference between those two srs.
> Which one is epsg:900913 (aka epsg:3785
> http://www.spatialreference.org/ref/epsg/3785/) ?
> 
> My experience (importing an osm dump into postgis, then exporting to
> shapefiles) would let me think that the "legacy OSM mercator format"
> is epsg:3785. So, what's the other one ?

The other one should be epsg:3395

$ ./osm2pgsql -vh
...
Supported projections:
Latlong             (-l) SRS:  4326 (none)
WGS84 Mercator      (  ) SRS:  3395 +proj=merc +datum=WGS84  +k=1.0 +units=m +over +no_defs
Spherical Mercator  (-m) SRS:900913 +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs +over

The seconds line of the help should show (-M) for the legacy projection.
I've just fixed it in SVN.

   Jon