Merge pull request #2105 from lonvia/fix-use-of-records

[nominatim.git] / docs / api / Reverse.md

diff --git a/docs/api/Reverse.md b/docs/api/Reverse.md
index 0c3c3d6500ca33a1597bd30c28b291daf9594439..a1b46b0fc2c56505cdf9142021eee5bb3b34fd44 100644 (file)
--- a/docs/api/Reverse.md
+++ b/docs/api/Reverse.md
@@ -1,76 +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?<query>
+https://nominatim.openstreetmap.org/reverse?lat=<value>&lon=<value>&<params>

 ```
 
 ```
 

-* `format=[xml|json|jsonv2]`
+where `lat` and `lon` are latitude and longitutde 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.

 
 

-    * Output format.
-    * `jsonv2` adds the next fields to response:
-        * `place_rank`
-        * `category`
-        * `type`
-        * `importance`
-        * `addresstype`
+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]`
+
+See [Place Output Formats](Output.md) for details on each format. (Default: xml)

 
 * `json_callback=<string>`
 
 
 * `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.

 
 

-* `accept-language=<browser language string>`
+### Output details
+
+* `addressdetails=[0|1]`

 
 

-    * 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.
+Include a breakdown of the address into elements. (Default: 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**

 
 

-* `lat=<value>` `lon=<value>`
-    * The location to generate an address for
+* `extratags=[0|1]`
+
+Include additional information in the result if available,
+e.g. wikipedia link, opening hours. (Default: 0)
+
+
+* `namedetails=[0|1]`
+
+Include a list of alternative names in the results. These may include
+language variants, references, operator and brand. (Default: 0)
+
+
+### 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]`
 
 * `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`
 * `polygon_kml=1`

-    * Output geometry of results in kml format.
-

 * `polygon_svg=1`
 * `polygon_svg=1`

-    * Output geometry of results in svg format.
-

 * `polygon_text=1`
 * `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`
 
 * `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>`

 
 

-* `namedetails=1`
-    * Include a list of alternative names in the results.
-    * These may include language variants, references, operator and brand.
+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.

 
 

-### Example
+
+* `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)
+
+
+## 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)
 
 
 * [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)
 


@@ -89,7 +148,7 @@ https://nominatim.openstreetmap.org/reverse?<query>
       <postcode>B72</postcode>
       <country>United Kingdom</country>
       <country_code>gb</country_code>
       <postcode>B72</postcode>
       <country>United Kingdom</country>
       <country_code>gb</country_code>

-    </addressparts>   
+    </addressparts>

   </reversegeocode>
 ```
 
   </reversegeocode>
 ```
 


@@ -100,7 +159,7 @@ https://nominatim.openstreetmap.org/reverse?<query>
 ```json
 {
   "place_id":"134140761",
 ```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",
   "osm_type":"way",
   "osm_id":"280940520",
 "lat":"-34.4391708",


@@ -125,14 +184,102 @@ https://nominatim.openstreetmap.org/reverse?<query>
 }
 ```
 
 }
 ```
 

-### Hierarchy
-
-* Admin level => XML entity
-    * 2 => `<country>`
-    * 4 => `<state>`
-    * 5 => `<state_district>`
-    * 6
-    * 7 => `<county>`
-    * 8 => `<village>`
-    * 9 => `<city_district>`
-    * 10 => `<suburb>`
+##### Example with `format=geojson`
+
+* [https://nominatim.openstreetmap.org/reverse?format=geojson&lat=44.50155&lon=11.33989](https://nominatim.openstreetmap.org/reverse?format=geojson&lat=44.50155&lon=11.33989)
+
+```json
+{
+  "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](https://nominatim.openstreetmap.org/reverse?format=geocodejson&lat=60.2299&lon=11.1663)
+
+```json
+{
+  "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
+      ]
+    }
+  }
+}
+```
+