Merge pull request #3542 from lonvia/remove-legacy-tokenizer

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

diff --git a/docs/api/Reverse.md b/docs/api/Reverse.md
index 999827a1aa3655e9c4f1684880a203872063732c..e646818f0e4fd0614451cb9989ddcde5d728d760 100644 (file)
--- a/docs/api/Reverse.md
+++ b/docs/api/Reverse.md
@@ -1,70 +1,216 @@
-## 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 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

 
 

-### 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 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.
+
+
+!!! tip
+    The reverse API allows a lookup of object by coordinate. If you want
+    to look up an object by ID, use the [Address Lookup API](Lookup.md) 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](Output.md) 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](https://en.wikipedia.org/wiki/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.

 
 

-    * Output format.
-    * `jsonv2` adds the next fields to response:
-        * `place_rank`
-        * `category`
-        * `type`
-        * `importance`
-        * `addresstype`

 
 

-* `json_callback=<string>`
+### Language of results

 
 

-    * Wrap json output in a callback function (JSONP) i.e. `<string>(<json>)` 
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| accept-language | browser language string | content of "Accept-Language" HTTP header |

 
 

-* `accept-language=<browser language string>`
+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).

 
 

-    * 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.
+!!! 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 contrary always
+    send the currently chosen browser language.

 
 

-* `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
+### Result restriction

 
 

-* `zoom=[0-18]`
-    * Level of detail required where `0` is country and `18` is house/building
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| zoom      | 0-18  | 18      |

 
 

-* `addressdetails=[0|1]`
-    * defaults to 0
-    * Include a breakdown of the address into elements
+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:

 
 

-* `email=<valid email address>`
+ 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

 
 

-    * 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.
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| layer     | comma-separated list of: `address`, `poi`, `railway`, `natural`, `manmade` | _unset_ (no restriction) |

 
 

-* `polygon_kml=1`
-    * Output geometry of results in kml format.
+The layer filter allows to select places by themes.

 
 

-* `polygon_svg=1`
-    * Output geometry of results in svg format.
+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.

 
 

-* `polygon_text=1`
-    * Output geometry of results as a WKT.
+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.

 
 

-* `extratags=1`
-    * Include additional information in the result if available, e.g. wikipedia link, opening hours.
+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.

 
 

-* `namedetails=1`
-    * Include a list of alternative names in the results.
-    * These may include language variants, references, operator and brand.
+The `natural` layer collects features like rivers, lakes and mountains while
+the `manmade` layer functions as a catch-all for features not covered by the
+other layers.

 
 

-### Example
+
+### 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](https://operations.osmfoundation.org/policies/nominatim/) 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

 
 * [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)
 


@@ -83,7 +229,7 @@ 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>
 ```
 


@@ -94,10 +240,10 @@ 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",
   "osm_type":"way",
   "osm_id":"280940520",

-"lat":"-34.4391708",
+  "lat":"-34.4391708",

   "lon":"-58.7064573",
   "place_rank":"26",
   "category":"highway",
   "lon":"-58.7064573",
   "place_rank":"26",
   "category":"highway",


@@ -119,14 +265,102 @@ 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
+      ]
+    }
+  }
+}
+```
+