[Talk-ca] Import of large features in Canvec

[Frank Steggink]

Hi all,

Today I have (finally) worked on large features in Canvec data (forests, 
water, etc.), and I have come up with a method how to deal with them. 
This currently involves PostGIS, but maybe I'll use GEOS or another 
method, so that it isn't necessary to load data in a DB. More details 
will follow soon, since I need to clean up code / sort out things a bit, 
and eventually integrate it into the canvec_to_osm.py script.

Right now I've uploaded (only) wooded areas in the Charlevoix region in 
Quebec. This already makes the map look entirely different! The result 
can be found here [1]. Changesets: [2] and [3].

You'll see faint horizontal and vertical lines crisscrossing the area. 
This is an artifact of making the features smaller (0.1 x 0.05 degrees). 
This will be dealt with with the "gamma" option which is part of the new 
Mapnik 0.7.0 release. This will probably be used in a couple of weeks on 
osm.org. See [4] for more info.

Cheers,

Frank

[1] 
http://www.openstreetmap.org/?lat=47.625&lon=-70.25&zoom=11&layers=B000FTFT
[2] http://www.openstreetmap.org/browse/changeset/3707953
[3] http://www.openstreetmap.org/browse/changeset/3708062
[4] http://trac.mapnik.org/wiki/PolygonSymbolizer