# Reverse Geocoding
-Reverse geocoding generates an address from a latitude and longitude or from
-an OSM object.
+Reverse geocoding generates an address from a coordinate given as
+latitude and longitude.
-## Parameters
+## 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?<query>
+https://nominatim.openstreetmap.org/reverse?lat=<value>&lon=<value>&<params>
```
-There are two ways how the requested location can be specified:
+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.
-* `lat=<value>` `lon=<value>`
- A geographic location to generate an address for. The coordiantes must be
- in WGS84 format.
+!!! 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](Lookup.md) instead.
-* `osm_type=[N|W|R]` `osm_id=<value>`
+!!! 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.
- A specific OSM node(N), way(W) or relation(R) to return an address for.
-In both cases exactly one object is returned. The two input paramters cannot
-be used at the same time. Both accept the additional optional parameters listed
-below.
+## Parameters
+
+This section lists additional parameters to further influence the output.
### Output format
-* `format=[xml|json|jsonv2|geojson|geocodejson]`
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| format | one of: `xml`, `json`, `jsonv2`, `geojson`, `geocodejson` | `xml` |
+
+See [Place Output Formats](Output.md) for details on each format.
+
-See [Place Output Formats](Output.md) for details on each format. (Default: html)
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| json_callback | function name | _unset_ |
-* `json_callback=<string>`
+When given, then JSON output will be wrapped in a callback function with
+the given name. See [JSONP](https://en.wikipedia.org/wiki/JSONP) for more
+information.
-Wrap json output in a callback function ([JSONP](https://en.wikipedia.org/wiki/JSONP)) i.e. `<string>(<json>)`.
Only has an effect for JSON output formats.
+
### Output details
-* `addressdetails=[0|1]`
+| 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.
-Include a breakdown of the address into elements. (Default: 1)
+!!! 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.
-* `extratags=[0|1]`
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| extratags | 0 or 1 | 0 |
-Include additional information in the result if available,
-e.g. wikipedia link, opening hours. (Default: 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.
-* `namedetails=[0|1]`
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| namedetails | 0 or 1 | 0 |
-Include a list of alternative names in the results. These may include
-language variants, references, operator and brand. (Default: 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
-* `accept-language=<browser language string>`
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| accept-language | browser language string | content of "Accept-Language" HTTP header |
-Preferred language order for showing search results, overrides the value
-specified in the "Accept-Language" HTTP header.
-Either use a standard RFC2616 accept-language string or a simple
-comma-separated list of language codes.
+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](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language).
-### Result limitation
+!!! 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.
-* `zoom=[0-18]`
-Level of detail required for the address. Default: 18. This is a number that corresponds
-roughly to the zoom level used in map frameworks like Leaflet.js, Openlayers etc.
+### 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
5 | state
8 | county
10 | city
- 14 | suburb
- 16 | street
+ 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
-* `polygon_geojson=1`
-* `polygon_kml=1`
-* `polygon_svg=1`
-* `polygon_text=1`
+| 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 |
-Output geometry of results as a GeoJSON, KML, SVG or WKT. Only one of these
-options can be used at a time. (Default: 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.
-* `polygon_threshold=0.0`
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| polygon_threshold | floating-point number | 0.0 |
-Simplify the output geometry before returning. The parameter is the
+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 result. (Default: 0.0)
+geometry. Topology is preserved in the geometry.
+
### Other
-* `email=<valid email address>`
+| 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](https://operations.osmfoundation.org/policies/nominatim/) for more details.
+address to identify your requests. See Nominatim's
+[Usage Policy](https://operations.osmfoundation.org/policies/nominatim/) for more details.
-* `debug=[0|1]`
+| 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 (rough) HTML format.
-This overrides the specified machine readable format. (Default: 0)
+"search loop" logic, and SQL queries. The output is HTML format.
+This overrides the specified machine readable format.
## Examples
<postcode>B72</postcode>
<country>United Kingdom</country>
<country_code>gb</country_code>
- </addressparts>
+ </addressparts>
</reversegeocode>
```
```json
{
"place_id":"134140761",
- "licence":"Data © OpenStreetMap contributors, ODbL 1.0. http:\/\/www.openstreetmap.org\/copyright",
+ "licence":"Data © OpenStreetMap contributors, ODbL 1.0. https:\/\/www.openstreetmap.org\/copyright",
"osm_type":"way",
"osm_id":"280940520",
-"lat":"-34.4391708",
+ "lat":"-34.4391708",
"lon":"-58.7064573",
"place_rank":"26",
"category":"highway",
projects / nominatim.git / blobdiff