OSM to Shapefile question

The shapefile format has a lot of limitations, so it is not possible to create a shapefile with all the information from OSM, so when you convert you have to decide what to include.

You don't describe what data you actually need, so it is hard to say for sure what is the best solution for you. If you need more than just simple shapes, you might be better off importing the planet file (or one of the extracts from Geofabrik or Cloudmade) into a PostGIS database.

Again depending on your needs, there are several ways to do that. Some of the options are: Osm2pgsql, Imposm and Osmosis

With Osmosis, PostgreSQL and PostGIS you can do something like this:

Create a PostGIS and hstore enabled database and setup the pgsnapshot schema, use Osmosis to import the data:

osmosis --read-pbf file=denmark.osm.pbf outPipe.0=1 --write-pgsql database=osm user=XXX password=XXX inPipe.0=1

Then create and index new qid columns to make QGIS happy:

CREATE SEQUENCE nodes_qid_seq;
ALTER TABLE nodes ADD COLUMN qid integer NOT NULL DEFAULT nextval('nodes_qid_seq');
CREATE UNIQUE INDEX nodes_qid ON nodes (qid ASC NULLS LAST);
ALTER TABLE nodes ADD CONSTRAINT unique_nodes_qid UNIQUE (qid);

CREATE SEQUENCE ways_qid_seq;
ALTER TABLE ways ADD COLUMN qid integer NOT NULL DEFAULT nextval('ways_qid_seq');
CREATE UNIQUE INDEX ways_qid ON ways (qid ASC NULLS LAST);
ALTER TABLE ways ADD CONSTRAINT unique_ways_qid UNIQUE (qid);

When you use the pgsnapshot schema, all the tags are stored in a hstore column. To make it easier to work with from QGIS, you can create views like this:

CREATE OR REPLACE VIEW "Amenities" AS 
  SELECT nodes.qid, nodes.tags -> 'amenity' AS amenity, nodes.tags -> 'leisure' AS leisure, 
    nodes.tags -> 'sport' AS sport, nodes.tags -> 'tourism' AS tourism, nodes.geom
  FROM nodes
  WHERE nodes.tags ? 'amenity' OR nodes.tags ? 'leisure' OR nodes.tags ? 'sport' OR nodes.tags ? 'tourism'
UNION ALL 
  SELECT ways.qid, ways.tags -> 'amenity' AS amenity, ways.tags -> 'leisure' AS leisure, 
    ways.tags -> 'sport' AS sport, ways.tags -> 'tourism' AS tourism, ways.linestring AS geom
  FROM ways
  WHERE ways.tags ? 'amenity' OR ways.tags ? 'leisure' OR ways.tags ? 'sport' OR ways.tags ? 'tourism';

CREATE OR REPLACE VIEW "Roads" AS 
  SELECT w.qid, w.tags -> 'highway' AS highway, w.tags -> 'foot' AS foot, w.tags -> 'bicycle' AS bicycle, 
    w.tags -> 'tracktype' AS tracktype, w.tags -> 'access' AS access, w.tags -> 'surface' AS surface, 
    w.tags -> 'sac_scale' AS sac_scale, w.tags -> 'mtb:scale' AS mtb_scale, w.linestring
  FROM ways w
  WHERE w.tags ? 'highway' OR w.tags ? 'foot' OR w.tags ? 'bicycle' OR w.tags ? 'tracktype' OR 
    w.tags ? 'access' OR w.tags ? 'surface' OR w.tags ? 'sac_scale' OR w.tags ? 'mtb:scale';

CREATE OR REPLACE VIEW "Walkable" AS 
  SELECT "Roads".qid, "Roads".highway, "Roads".foot, "Roads".bicycle, "Roads".tracktype, "Roads".access, 
    "Roads".surface, "Roads".sac_scale, "Roads".mtb_scale, "Roads".linestring
    FROM "Roads"
  WHERE COALESCE("Roads".foot, 'empty') <> 'no' AND 
    (COALESCE("Roads".access, 'empty') <> ALL (ARRAY['private', 'no', 'restricted', 'emergency'])) AND 
    (COALESCE("Roads".highway, 'empty') <> ALL (ARRAY['primary', 'cycleway', 'trunk', 'motorway', 'primary_link', 'trunk_link', 'motorway_link', 'motorway_junction']));

Then in QGIS, you can add the Amenities and Walkable views as PostGIS layers.

You should change the views to use your own classifications.

You can also use osm2pgsql and change the import style to create a schema that matches your needs.

There are no fixed rules for how anything should be tagged in OSM, so your biggest task is probably identifying what tag/value combinations you should use to make your classifications.

You can start by looking at some of these keys and especially their link to taginfo on the right side of the page - the "values" tab can give you an idea about values you should consider:

highway, foot, bicycle, tracktype, surface, access, mtb:scale and sac_scale.

/Jais