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Custom Areas and Country Rules

GraphHopper lets you specify arbitrary (custom) areas using the custom_areas.directory setting in config.yml. During import all areas that contain a given way will be available for all TagParsers and FlagEncoders. This way you can adjust or override the corresponding handleWayTags methods to modify encoded values based on the areas that contain a given edge.

As a special case of custom areas, GraphHopper automatically includes country borders and finds the country for every imported OSM way. See the countries.geojson file for GraphHopper's country borders and the next section for some details about this file. Just as for custom areas the country information will be available to all TagParsers and FlagEncoders during import, and of course can also be used to modify encoded values. For example GraphHopper stores the country information using the CountryParser and the Country encoded value for every edge. Add country to graph.encoded_values in config.yml to enable this. To change encoded values like max_speed and access depending on the country it is probably easier to use country rules (see below).

GraphHopper uses so-called country rules to modify the routing behavior depending on country-specific details. There is a separate implementation of the CountryRule interface for every country (unless it has not been created yet). For example the AustriaCountryRule changes the default accessibility for highway=track to access=yes, while the GermanyCountryRule changes it to access=destination. More information about such country-specific rules can be found in the OSM wiki for access restrictions and maximum speeds. Feel free to add country rules for your country and contribute to GraphHopper!

Note about the country rules used by GraphHopper

The countries.geojson file originates from Openstreetmap and has been downloaded via https://osm-boundaries.com

The GeoJSON was generated with https://www.mapshaper.org/ and can be recreated with these steps:

  • download all country boundaries with admin level 2 (download about 1/3 of all countries at once to avoid download limit)
  • import the GeoJSON files as separate layers with the options detect line intersections, snap vertices and the import option combine-files
  • merge the layers into one using the console command merge-layers
  • fix issues in the dataset using the console command clean
  • simplify
    • enable prevent shape removal
    • select visvalingam / weighted area
    • use 2.0%
  • repair intersections
  • export as GeoJSON