X-Git-Url: https://git.openstreetmap.org./nominatim.git/blobdiff_plain/879f818d810d9418183f62fe2f991347aae78569..92e2f5ca8e270b4a236afac7242bc1e7fbf35c52:/docs/api/Reverse.md diff --git a/docs/api/Reverse.md b/docs/api/Reverse.md index ee8c3ea5..c133750c 100644 --- a/docs/api/Reverse.md +++ b/docs/api/Reverse.md @@ -1,77 +1,135 @@ -## 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 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. + + +## Parameters + +The main format of the reverse API is -### Parameters ``` -https://nominatim.openstreetmap.org/reverse? +https://nominatim.openstreetmap.org/reverse?lat=&lon=& ``` +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. + +Additional parameters 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.md) + 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=` - * Wrap json output in a callback function (JSONP) i.e. `()` +Wrap JSON output in a callback function ([JSONP](https://en.wikipedia.org/wiki/JSONP)) i.e. `()`. +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=` - * 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=` - * 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=` `lon=` - * The location to generate an address for + +### Language of results + +* `accept-language=` + +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=` + 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=` + +If you are making a large number of requests, 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) @@ -90,7 +148,7 @@ https://nominatim.openstreetmap.org/reverse? B72 United Kingdom gb - + ``` @@ -101,10 +159,10 @@ https://nominatim.openstreetmap.org/reverse? ```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", @@ -225,14 +283,3 @@ https://nominatim.openstreetmap.org/reverse? } ``` -### Hierarchy - -* Admin level => XML entity - * 2 => `` - * 4 => `` - * 5 => `` - * 6 - * 7 => `` - * 8 => `` - * 9 => `` - * 10 => ``