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Juno Reverse Geocoder

This is a set of SQL scripts working on a PostGIS database that for a given location return a structured address: from a house number up to a country. Together this makes for a reverse geocoder, which Juno Inc. uses internally.

Installation

Starting it should be simple:

  • Install PostgreSQL, PostGIS, and osm2pgsql.
  • Create a geocoder database in PostgreSQL.
  • Do create extension postgis on the database.
  • Download an OpenStreetMap extract for your area.
  • Run run.sh <file.osm.pbf> to upload the area into the database and start the geocoder.

Docker container

Check docker container section

Usage

The REST API is generally compatible with Nominatim's. No details or language modifiers work. Only jsonv2 format is supported (no need to specify it). Coordinates and identifiers are output as strings.

Sample call:

http://localhost:5000/reverse?lon=-73.80401&lat=40.97230

Sample response:

{
    "address": {
        "country": "United States",
        "state": "New York",
        "county": "Westchester County",
        "locality": "Eastchester",
        "town": "Town of Eastchester",
        "postcode": "10583",
        "road": "White Plains Road",
        "house_number": "750"
    },
    "lat": "40.972219900389",
    "lon": "-73.8037561",
    "name": "Lord and Taylor",
    "display_name": "750 White Plains Road",
    "osm_id": 3111837409,
    "osm_type": "node",
    "type": "poi"
}

Note that non-address tags are dropped, and the only information that remains is whether a point is a POI or not. The type can be one of admin, road, building, address, or poi.

Error Messages

When there is an error in URL arguments (e.g. non-numeric coordinate or osm_id), you'll get HTTP 400 with a json containing a single "message" key.

When an object has not been found, you'll get HTTP 404 with a json containing a single "error" key.

Server errors obviously lead to HTTP 500 errors, although these should not happen.

Contributing

The reverse geocoder is basically two sets of SQL scripts inside the sql directory: one for preprocessing an osm2pgsql database (sql/prepare) and another for doing queries (sql/query). If you aim to improve the quality, go there.

Other scripts and files are merely interfaces to use and access a database with these scripts. They should just work.

Tests reside in the tests directory and are written with behave. Look into tests/features to get human-readable test cases. Feel free to add tests if you think they should cover more cases. Have a look at tests marked @wip: maybe you'll have an idea how to update SQL scripts to accomodate these.

At the moment tests rely on actual OpenStreetMap data which might be not great, since OSM is being constantly improved, so some of these cases would get simpler with time. A good task would be to extract data for each of these tests into a separate osm.pbf file and make the testing framework install a separate instance of a database.

Author and License

The geocoder was written by Ilya Zverev for Juno, published under the Apache 2.0 License.