Elixir-Overpass

A Elixir wrapper to access the Overpass API.

Have a look at the documentation to find additional information.

Based on https://github.com/DinoTools/python-overpy http://python-overpy.readthedocs.org/

Features

• Query Overpass API
• Parse JSON and XML response data
• Additional helper functions

Installation

As available in Hex, the package can be installed as:

1. Add overpass to your list of dependencies in mix.exs:

   def deps do [{:overpass, "~> 0.1.0"}] end

2. Ensure overpass is started before your application:

   def application do [applications: [:overpass]] end

3. Add the Overpass API URL to your config in config/config.exs:

   config :overpass, url: "http://overpass-api.de/api/interpreter"

Examples

Query the API

Using QL:

{:ok, {:xml, response}} = Overpass.API.query("""
  node["name"="Gielgen"];
  out body;
""")

{:ok, {:json, response}} = Overpass.API.query("""
  [out:json];
  node["name"="Gielgen"];
  out body;
""")

Using XML:

{:ok, {:xml, response}} = Overpass.API.query("""
  <osm-script>
    <query type="node">
      <has-kv k="name" v="Gielgen"/>
    </query>
    <print/>
  </osm-script>
""")

{:ok, {:json, response}} = Overpass.API.query("""
  <osm-script output="json">
    <query type="node">
      <has-kv k="name" v="Gielgen"/>
    </query>
    <print/>
  </osm-script>
""")

Query the API and Parse the Result

{:ok, %Overpass.Response{nodes: nodes, ways: ways, relations: relations}} = Overpass.API.query("""
  (
    node
      ["amenity"="fire_station"]
      (50.6,7.0,50.8,7.3);
    way
      ["amenity"="fire_station"]
      (50.6,7.0,50.8,7.3);
    rel
      ["amenity"="fire_station"]
      (50.6,7.0,50.8,7.3);
  );
  (._;>;);
  out;
""") |> Overpass.Parser.parse()

Get the nodes for a way

{:ok, %Overpass.Response{nodes: nodes, ways: ways, relations: _relations}} = Overpass.API.query("""
  (
    node
      ["amenity"="fire_station"]
      (50.6,7.0,50.8,7.3);
    way
      ["amenity"="fire_station"]
      (50.6,7.0,50.8,7.3);
    rel
      ["amenity"="fire_station"]
      (50.6,7.0,50.8,7.3);
  );
  (._;>;);
  out;
""") |> Overpass.Parser.parse()

# Get nodes for the way from the responded nodes
list_with_nodes = Overpass.Way.get_nodes(nodes, List.first(ways))

# Get all nodes for the way (new Overpass.Query)
list_with_nodes = Overpass.Way.get_nodes(nodes, List.first(ways), true)

Helper

TODO

License

The MIT License (MIT)