-## Reverse Geocoding
+# Reverse Geocoding
-Reverse geocoding generates an address from a latitude and longitude. The optional `zoom` parameter specifies the level of detail required in terms of something suitable for a Leaflet.js/OpenLayers/etc. zoom level.
+Reverse geocoding generates an address from a latitude and longitude.
+
+## How it works
+
+The reveser 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.
+
+
+## Parameters
+
+The main format of the reverse API is
-### Parameters
```
-https://nominatim.openstreetmap.org/reverse?<query>
+https://nominatim.openstreetmap.org/reverse?lat=<value>&lon=<value>&<params>
```
+where `lat` and `lon` are latitude and longitutde of a coordinare in WGS84
+projection. The API returns exactly one result or an error when the coordinate
+is in an area with no OSM data coverage.
+
+Additional paramters are accepted as listed below.
+
+!!! warning "Deprecation warning"
+ The reverse API used to allow address lookup for a single OSM object by
+ its OSM id. This use is now deprecated. Use the [Address Lookup API](../Lookup)
+ instead.
+
+### Output format
+
* `format=[xml|json|jsonv2|geojson|geocodejson]`
- * Output format
- * defaults to `xml`
- * `jsonv2` adds the next fields to response:
- * `place_rank`
- * `category`
- * `type`
- * `importance`
- * `addresstype`
+See [Place Output Formats](Output.md) for details on each format. (Default: xml)
* `json_callback=<string>`
- * Wrap json output in a callback function (JSONP) i.e. `<string>(<json>)`
+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]`
+
+Include a breakdown of the address into elements. (Default: 1)
+
+
+* `extratags=[0|1]`
+
+Include additional information in the result if available,
+e.g. wikipedia link, opening hours. (Default: 0)
-* `accept-language=<browser language string>`
- * Preferred language order for showing search results, overrides the value specified in the "Accept-Language" HTTP header.
- * Either uses standard rfc2616 accept-language string or a simple comma separated list of language codes.
+* `namedetails=[0|1]`
-* `osm_type=[N|W|R]` `osm_id=<value>`
- * A specific osm node / way / relation to return an address for
- * **Please use this in preference to lat/lon where possible**
+Include a list of alternative names in the results. These may include
+language variants, references, operator and brand. (Default: 0)
-* `lat=<value>` `lon=<value>`
- * The location to generate an address for
+
+### Language of results
+
+* `accept-language=<browser language string>`
+
+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.
+
+### Result limitation
* `zoom=[0-18]`
- * Level of detail required where `0` is country and `18` is house/building
-* `addressdetails=[0|1]`
- * defaults to 0
- * Include a breakdown of the address into elements
+Level of detail required for the address. Default: 18. 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:
-* `email=<valid email address>`
+ zoom | address detail
+ -----|---------------
+ 3 | country
+ 5 | state
+ 8 | county
+ 10 | city
+ 14 | suburb
+ 16 | major streets
+ 17 | major and minor streets
+ 18 | building
- * If you are making large numbers of request please include a valid email address or alternatively include your email address as part of the User-Agent string.
- * This information will be kept confidential and only used to contact you in the event of a problem, see [Usage Policy](https://operations.osmfoundation.org/policies/nominatim/) for more details.
-* `polygon_geojson=1`
- * Output geometry of results in geojson format.
+### Polygon output
+* `polygon_geojson=1`
* `polygon_kml=1`
- * Output geometry of results in kml format.
-
* `polygon_svg=1`
- * Output geometry of results in svg format.
-
* `polygon_text=1`
- * Output geometry of results as a WKT.
+
+Output geometry of results as a GeoJSON, KML, SVG or WKT. Only one of these
+options can be used at a time. (Default: 0)
* `polygon_threshold=0.0`
- * defaults to 0.0
- * Simplify the output geometry before returning. The parameter is the
- tolerance in degrees with which the geometry may differ from the original
- geometry. Topology is preserved in the result.
-* `extratags=1`
- * Include additional information in the result if available, e.g. wikipedia link, opening hours.
+Return a simplified version of the output geometry. The parameter is the
+tolerance in degrees with which the geometry may differ from the original
+geometry. Topology is preserved in the result. (Default: 0.0)
+
+### Other
+
+* `email=<valid email address>`
+
+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.
+
+
+* `debug=[0|1]`
+
+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)
-* `namedetails=1`
- * Include a list of alternative names in the results.
- * These may include language variants, references, operator and brand.
-### Example
+## Examples
* [https://nominatim.openstreetmap.org/reverse?format=xml&lat=52.5487429714954&lon=-1.81602098644987&zoom=18&addressdetails=1](https://nominatim.openstreetmap.org/reverse?format=xml&lat=52.5487429714954&lon=-1.81602098644987&zoom=18&addressdetails=1)
<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",
}
```
-### Hierarchy
-
-* Admin level => XML entity
- * 2 => `<country>`
- * 4 => `<state>`
- * 5 => `<state_district>`
- * 6
- * 7 => `<county>`
- * 8 => `<village>`
- * 9 => `<city_district>`
- * 10 => `<suburb>`
projects / nominatim.git / blobdiff