High Road

This may be the last OpenStreetMap road query you will ever need.

Between Mapnik, Cascadenik, and Carto, you’ve got a few options for rendering OSM data to tiles. High Road makes it easier to draw the road bits by hiding complicated PostGIS queries behind views, so that you can declutter your layer names while ensuring that you’re using the right selection of roads for each zoom level.

There’s a sample Cascadenik style and layer file, but the real action is in high_road_views-setup.pgsql, where you’ll find a comprehensive set of Postgres views against the usual planet_osm_line table produced by Osm2pgsql.

To use High Road, run the source of high_road_views-setup.pgsql against your existing OSM rendering database and check out the sample files to understand what each query is doing.

High Road is made by Michal Migurski, Nathaniel Kelso and Geraldine Sarmiento of Stamen Design.

Setup

High Road can be applied to an existing OpenStreetMap rendering database created with osm2pgsql (http://wiki.openstreetmap.org/wiki/Osm2pgsql). Using the command-line psql utility, you can add High Road views like this:

psql -U username -f high_road_views-setup.pgsql databasename

The views here assume that you've created your database using the default settings of osm2pgsql, including the prefix of "planet_osm". If you've chosen a different prefix, you should find every instance of "planet_osm" in the script below and replace is with your chosen prefix. The typical username for OSM databases is osm and the typical databasename is planet_osm.

More details in the high_road_views-setup.pgsql file comments.

Removal, upgrading

High Road can be removed from an existing OpenStreetMap rendering database.

NOTE: To upgrade your OSM planet, High Road will need to be removed before OSM import, then setup again after OSM import.

Using the command-line psql utility, you can remove High Road views like this:

 psql -U username -f high_road_views-remove.pgsql databasename

This is the same as if you logged into Postgres:

psql -U username -d databasename

And dropped the views manually:

DROP VIEW planet_osm_line_z15plus CASCADE;
DROP VIEW planet_osm_line_z14 CASCADE;
DROP VIEW planet_osm_line_z13 CASCADE;
DROP VIEW planet_osm_line_z12 CASCADE;
DROP VIEW planet_osm_line_z11 CASCADE;
DROP VIEW planet_osm_line_z10 CASCADE;

Details

Taking a cue from Justin O’Bierne’s dearly-departed 41Latitude blog, High Road ensures that each zoom level contains exactly three distinct levels of road: highways, major roads, and minor roads, a simplification of OpenStreetMap’s conventional six-level hierarchy.

At distant zoom levels, local and residential streets are omitted. Bold, simple highways dominate the map, and the visual layering is categorical to clearly separate each road type.

Oakland, z11