[ gpsdrive ] Mapnik Projection used by gpsdrive

[Jan-Benedict Glaw]

On Mon, 2008-09-22 15:37:01 +0200, Guenther Meyer <d.s.e at sordidmusic.com> wrote:
> Am Sonntag 21 September 2008 schrieb Christoph Metz:
> > i don't know who is always changing this. i have to look in the svn
> > log but the second projection is correct.
> >
> really?
> maybe they changed something in mapnik/osm2pgsql?

osm2pgsql was changed. The "old" version wrote something that's
compatible with the "short" projection string, while up-to-date
versions (eg. *not* those of the osm2pgsql Debian package....) write
something that's compatible with the "long" string. The newer
osm2pgsql versions can also behave like the old versions, if the "-M"
command line option is used.

But since OSM switched, I think the best way for gpsdrive would be to
also use the "new" scheme and to force users to update their
databases, caches and osm2pgsql. The benefit would be that they only
need one database for general OSM/Mapnik use and gpsdrive, instead of
two. (Or fiddle with projection parameters.)

As a side note: If you use (or want to follow) the *current* osm.xml
from OSM SVN, you'll loose the amenity layer (eg. parking places,
recycling boxes, ...) because the current osm2pgsql's default.style
converts an additional column, which is missing from the old version
and required by up-to-date osm.xml files (from SVN). Unfortunately,
Mapnik fails quietly if a filter references a non-existing column and
doesn't draw the whole layer. (And my missing C++ skills won't really
allow me to work on that.)

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw at lug-owl.de              +49-172-7608481
Signature of: "Debugging is twice as hard as writing the code in the first place.
the second  :  Therefore, if you write the code as cleverly as possible, you are,
               by definition, not smart enough to debug it." - Brian W. Kernighan
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.gpsdrivers.org/pipermail/gpsdrive/attachments/20080923/c84337b7/attachment.bin>