Nominatim/docs/api/Reverse.md
2023-08-30 09:57:46 +02:00

12 KiB

Reverse Geocoding

Reverse geocoding generates an address from a coordinate given as latitude and longitude.

How it works

The reverse geocoding API does not exactly compute the address for the coordinate it receives. It works by finding the closest suitable OSM object and returning its address information. This may occasionally lead to unexpected results.

First of all, Nominatim only includes OSM objects in its index that are suitable for searching. Small, unnamed paths for example are missing from the database and can therefore not be used for reverse geocoding either.

The other issue to be aware of is that the closest OSM object may not always have a similar enough address to the coordinate you were requesting. For example, in dense city areas it may belong to a completely different street.

Endpoint

The main format of the reverse API is

https://nominatim.openstreetmap.org/reverse?lat=<value>&lon=<value>&<params>

where lat and lon are latitude and longitude of a coordinate in WGS84 projection. The API returns exactly one result or an error when the coordinate is in an area with no OSM data coverage.

!!! danger "Deprecation warning" The reverse API used to allow address lookup for a single OSM object by its OSM id for [PHP-only]. The use is considered deprecated. Use the Address Lookup API instead.

!!! danger "Deprecation warning" The API can also be used with the URL https://nominatim.openstreetmap.org/reverse.php. This is now deprecated and will be removed in future versions.

Parameters

This section lists additional parameters to further influence the output.

Output format

Parameter Value Default
format one of: xml, json, jsonv2, geojson, geocodejson xml

See Place Output Formats for details on each format.

Parameter Value Default
json_callback function name unset

When given, then JSON output will be wrapped in a callback function with the given name. See JSONP for more information.

Only has an effect for JSON output formats.

Output details

Parameter Value Default
addressdetails 0 or 1 1

When set to 1, include a breakdown of the address into elements. The exact content of the address breakdown depends on the output format.

!!! tip If you are interested in a stable classification of address categories (suburb, city, state, etc), have a look at the geocodejson format. All other formats return classifications according to OSM tagging. There is a much larger set of categories and they are not always consistent, which makes them very hard to work with.

Parameter Value Default
extratags 0 or 1 0

When set to 1, the response include any additional information in the result that is available in the database, e.g. wikipedia link, opening hours.

Parameter Value Default
namedetails 0 or 1 0

When set to 1, include a full list of names for the result. These may include language variants, older names, references and brand.

Language of results

Parameter Value Default
accept-language browser language string content of "Accept-Language" HTTP header

Preferred language order for showing search results. This may either be a simple comma-separated list of language codes or have the same format as the "Accept-Language" HTTP header.

!!! tip First-time users of Nominatim tend to be confused that they get different results when using Nominatim in the browser versus in a command-line tool like wget or curl. The command-line tools usually don't send any Accept-Language header, prompting Nominatim to show results in the local language. Browsers on the contratry always send the currently chosen browser language.

Result restriction

Parameter Value Default
zoom 0-18 18

Level of detail required for the address. This is a number that corresponds roughly to the zoom level used in XYZ tile sources in frameworks like Leaflet.js, Openlayers etc. In terms of address details the zoom levels are as follows:

zoom address detail
3 country
5 state
8 county
10 city
12 town / borough
13 village / suburb
14 neighbourhood
15 any settlement
16 major streets
17 major and minor streets
18 building
Parameter Value Default
layer comma-separated list of: address, poi, railway, natural, manmade unset (no restriction)

The layer filter allows to select places by themes.

The address layer contains all places that make up an address: address points with house numbers, streets, inhabited places (suburbs, villages, cities, states etc.) and administrative boundaries.

The poi layer selects all point of interest. This includes classic points of interest like restaurants, shops, hotels but also less obvious features like recycling bins, guideposts or benches.

The railway layer includes railway infrastructure like tracks. Note that in Nominatim's standard configuration, only very few railway features are imported into the database.

The natural layer collects feautures like rivers, lakes and mountains while the manmade layer functions as a catch-all for features not covered by the other layers.

Polygon output

Parameter Value Default
polygon_geojson 0 or 1 0
polygon_kml 0 or 1 0
polygon_svg 0 or 1 0
polygon_text 0 or 1 0

Add the full geometry of the place to the result output. Output formats in GeoJSON, KML, SVG or WKT are supported. Only one of these options can be used at a time.

Parameter Value Default
polygon_threshold floating-point number 0.0

When one of the polygon_* outputs is chosen, return a simplified version of the output geometry. The parameter describes the tolerance in degrees with which the geometry may differ from the original geometry. Topology is preserved in the geometry.

Other

Parameter Value Default
email valid email address unset

If you are making large numbers of request please include an appropriate email address to identify your requests. See Nominatim's Usage Policy for more details.

Parameter Value Default
debug 0 or 1 0

Output assorted developer debug information. Data on internals of Nominatim's "search loop" logic, and SQL queries. The output is HTML format. This overrides the specified machine readable format.

Examples

  <reversegeocode timestamp="Fri, 06 Nov 09 16:33:54 +0000" querystring="...">
    <result place_id="1620612" osm_type="node" osm_id="452010817">
      135, Pilkington Avenue, Wylde Green, City of Birmingham, West Midlands (county), B72, United Kingdom
    </result>
    <addressparts>
      <house_number>135</house_number>
      <road>Pilkington Avenue</road>
      <village>Wylde Green</village>
      <town>Sutton Coldfield</town>
      <city>City of Birmingham</city>
      <county>West Midlands (county)</county>
      <postcode>B72</postcode>
      <country>United Kingdom</country>
      <country_code>gb</country_code>
    </addressparts>
  </reversegeocode>
Example with format=jsonv2
{
  "place_id":"134140761",
  "licence":"Data © OpenStreetMap contributors, ODbL 1.0. https:\/\/www.openstreetmap.org\/copyright",
  "osm_type":"way",
  "osm_id":"280940520",
  "lat":"-34.4391708",
  "lon":"-58.7064573",
  "place_rank":"26",
  "category":"highway",
  "type":"motorway",
  "importance":"0.1",
  "addresstype":"road",
  "display_name":"Autopista Pedro Eugenio Aramburu, El Triángulo, Partido de Malvinas Argentinas, Buenos Aires, 1.619, Argentina",
  "name":"Autopista Pedro Eugenio Aramburu",
  "address":{
    "road":"Autopista Pedro Eugenio Aramburu",
    "village":"El Triángulo",
    "state_district":"Partido de Malvinas Argentinas",
    "state":"Buenos Aires",
    "postcode":"1.619",
    "country":"Argentina",
    "country_code":"ar"
  },
  "boundingbox":["-34.44159","-34.4370994","-58.7086067","-58.7044712"]
}
Example with format=geojson
{
  "type": "FeatureCollection",
  "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "place_id": "18512203",
        "osm_type": "node",
        "osm_id": "1704756187",
        "place_rank": "30",
        "category": "place",
        "type": "house",
        "importance": "0",
        "addresstype": "place",
        "name": null,
        "display_name": "71, Via Guglielmo Marconi, Saragozza-Porto, Bologna, BO, Emilia-Romagna, 40122, Italy",
        "address": {
          "house_number": "71",
          "road": "Via Guglielmo Marconi",
          "suburb": "Saragozza-Porto",
          "city": "Bologna",
          "county": "BO",
          "state": "Emilia-Romagna",
          "postcode": "40122",
          "country": "Italy",
          "country_code": "it"
        }
      },
      "bbox": [
        11.3397676,
        44.5014307,
        11.3399676,
        44.5016307
      ],
      "geometry": {
        "type": "Point",
        "coordinates": [
          11.3398676,
          44.5015307
        ]
      }
    }
  ]
}
Example with format=geocodejson

https://nominatim.openstreetmap.org/reverse?format=geocodejson&lat=60.2299&lon=11.1663

{
  "type": "FeatureCollection",
  "geocoding": {
    "version": "0.1.0",
    "attribution": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
    "licence": "ODbL",
    "query": "60.229917843587,11.16630979382"
  },
  "features": {
    "type": "Feature",
    "properties": {
      "geocoding": {
        "place_id": "42700574",
        "osm_type": "node",
        "osm_id": "3110596255",
        "type": "house",
        "accuracy": 0,
        "label": "1, Løvenbergvegen, Mogreina, Ullensaker, Akershus, 2054, Norway",
        "name": null,
        "housenumber": "1",
        "street": "Løvenbergvegen",
        "postcode": "2054",
        "county": "Akershus",
        "country": "Norway",
        "admin": {
          "level7": "Ullensaker",
          "level4": "Akershus",
          "level2": "Norway"
        }
      }
    },
    "geometry": {
      "type": "Point",
      "coordinates": [
        11.1658572,
        60.2301296
      ]
    }
  }
}