Merge remote-tracking branch 'upstream/master'

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

diff --git a/docs/api/Search.md b/docs/api/Search.md
index e2c55fa59d8406f2716e8f1deb1c01ede4012e11..ce081cab8a1df4b6879d9f8386b55dfc53b97033 100644 (file)
--- a/docs/api/Search.md
+++ b/docs/api/Search.md
@@ -1,142 +1,200 @@
+# Search queries

 
 

-## Search
-Nominatim indexes named (or numbered) features with the OSM data set and a subset of other unnamed features (pubs, hotels, churches, etc)
+The search API allows you to look up a location from a textual description
+or address. Nominatim supports structured and free-form search queries.

 
 

-Search terms are processed first left to right and then right to left if that fails.
+The search query may also contain
+[special phrases](https://wiki.openstreetmap.org/wiki/Nominatim/Special_Phrases)
+which are translated into specific OpenStreetMap (OSM) tags (e.g. Pub => `amenity=pub`).
+This can be used to narrow down the kind of objects to be returned.

 
 

-Both searches will work: [pilkington avenue, birmingham](//nominatim.openstreetmap.org/search?q=pilkington+avenue,birmingham), [birmingham, pilkington avenue](//nominatim.openstreetmap.org/search?q=birmingham,+pilkington+avenue)
+!!! warning
+    Special phrases are not suitable to query all objects of a certain type in an
+    area. Nominatim will always just return a collection of the best matches. To
+    download OSM data by object type, use the [Overpass API](https://overpass-api.de/).

 
 

-(Commas are optional, but improve performance by reducing the complexity of the search.)
+## Parameters

 
 

-Where house numbers have been defined for an area they should be used: [135 pilkington avenue, birmingham](//nominatim.openstreetmap.org/search?q=135+pilkington+avenue,+birmingham)
-
-### Special Keywords
-Various keywords are translated into searches for specific osm tags (e.g. Pub => amenity=pub).  A current list of [special phrases](https://wiki.openstreetmap.org/wiki/Nominatim/Special_Phrases) processed is available.
-
-### Parameters
+The search API has the following format:

 
 ```
    https://nominatim.openstreetmap.org/search?<params>
 
 ```
    https://nominatim.openstreetmap.org/search?<params>

-   https://nominatim.openstreetmap.org/search/<query>?<params>

 ```
 
 ```
 

-* `format=[html|xml|json|jsonv2|geojson|geocodejson]`
+The search term may be specified with two different sets of parameters:
+
+* `q=<query>`
+
+    Free-form query string to search for.
+    Free-form queries are processed first left-to-right and then right-to-left if that fails. So you may search for
+    [pilkington avenue, birmingham](https://nominatim.openstreetmap.org/search?q=pilkington+avenue,birmingham) as well as for
+    [birmingham, pilkington avenue](https://nominatim.openstreetmap.org/search?q=birmingham,+pilkington+avenue).
+    Commas are optional, but improve performance by reducing the complexity of the search.
+
+
+* `street=<housenumber> <streetname>`
+* `city=<city>`
+* `county=<county>`
+* `state=<state>`
+* `country=<country>`
+* `postalcode=<postalcode>`

 
 

-    * Output format
-    * defaults to `html`
+    Alternative query string format split into several parameters for structured requests.
+    Structured requests are faster but are less robust against alternative
+    OSM tagging schemas. **Do not combine with** `q=<query>` **parameter**.

 
 

+Both query forms accept the additional parameters listed below.
+
+### Output format
+
+* `format=[xml|json|jsonv2|geojson|geocodejson]`
+
+See [Place Output Formats](Output.md) for details on each format. (Default: jsonv2)
+
+!!! note
+    The Nominatim service at
+    [https://nominatim.openstreetmap.org](https://nominatim.openstreetmap.org)
+    has a different default behaviour for historical reasons. When the
+    `format` parameter is omitted, the request will be forwarded to the Web UI.

 
 * `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

 
 

-    * 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.
+* `addressdetails=[0|1]`

 
 

-* `q=<query>`
+Include a breakdown of the address into elements. (Default: 0)

 
 

-    * Query string to search for.
-    * Alternatively can be entered as:

 
 

-        * `street=<housenumber> <streetname>`
-        * `city=<city>`
-        * `county=<county>`
-        * `state=<state>`
-        * `country=<country>`
-        * `postalcode=<postalcode>`
-        
-      **(experimental)** Alternative query string format for structured requests. 
-Structured requests are faster and require fewer server resources. **Do not combine with `q=<query>` parameter**.
+* `extratags=[0|1]`

 
 

-* `countrycodes=<countrycode>[,<countrycode>][,<countrycode>]...`
+Include additional information in the result if available,
+e.g. wikipedia link, opening hours. (Default: 0)

 
 

-    * Limit search results to a specific country (or a list of countries).  
-    * `<countrycode>` should be the ISO 3166-1alpha2 code, e.g. `gb` for the United Kingdom, `de` for Germany, etc.

 
 

-* `viewbox=<x1>,<y1>,<x2>,<y2>`
-    * The preferred area to find search results. Any two corner points of the box are accepted in any order as long as they span a real box.
+* `namedetails=[0|1]`

 
 

-* `bounded=[0|1]`
-    * defaults to 0
-    * Restrict the results to only items contained with the viewbox (see above). 
-    * Restricting the results to the bounding box also enables searching by amenity only. 
-    * For example a search query of just `"[pub]"` would normally be rejected but with `bounded=1` will result in a list of items matching within the bounding box.
+Include a list of alternative names in the results. These may include
+language variants, references, operator and brand. (Default: 0)

 
 

-* `polygon=[0|1]`
-    * defaults to 0
-    * Output polygon outlines for items found **(deprecated, use one of the polygon_* parameters instead)**

 
 

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

 
 

-* `email=<valid email address>`
+* `accept-language=<browser language string>`
+
+Preferred language order for showing search results, overrides the value
+specified in the ["Accept-Language" HTTP header](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language).
+Either use a standard RFC2616 accept-language string or a simple
+comma-separated list of language codes.

 
 

-    * 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.
+### Result limitation
+
+* `countrycodes=<countrycode>[,<countrycode>][,<countrycode>]...`
+
+Limit search results to one or more countries. `<countrycode>` must be the
+[ISO 3166-1alpha2](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) code,
+e.g. `gb` for the United Kingdom, `de` for Germany.
+
+Each place in Nominatim is assigned to one country code based
+on OSM country boundaries. In rare cases a place may not be in any country
+at all, for example, in international waters.

 
 * `exclude_place_ids=<place_id,[place_id],[place_id]`
 
 
 * `exclude_place_ids=<place_id,[place_id],[place_id]`
 

-    * If you do not want certain openstreetmap objects to appear in the search result, give a comma separated list of the place_id's you want to skip. This can be used to broaden search results. For example, if a previous query only returned a few results, then including those here would cause the search to return other, less accurate, matches (if possible)
+If you do not want certain OSM objects to appear in the search
+result, give a comma separated list of the `place_id`s you want to skip.
+This can be used to retrieve additional search results. For example, if a
+previous query only returned a few results, then including those here would
+cause the search to return other, less accurate, matches (if possible).
+

 
 * `limit=<integer>`
 
 * `limit=<integer>`

-    * defaults to 10
-    * Limit the number of returned results.

 
 

-* `dedupe=[0|1]`
-    * defaults to 1
-    * Sometimes you have several objects in OSM identifying the same place or object in reality. The simplest case is a street being split in many different OSM ways due to different characteristics. 
-    * Nominatim will attempt to detect such duplicates and only return one match; this is controlled by the dedupe parameter which defaults to 1. Since the limit is, for reasons of efficiency, enforced before and not after de-duplicating, it is possible that de-duplicating leaves you with less results than requested.
+Limit the number of returned results. (Default: 10, Maximum: 50)

 
 

-* `debug=[0|1]`
-    * defaults to 0
-    * Output assorted developer debug information. Data on internals of nominatim "Search Loop" logic, and SQL queries. The output is (rough) HTML format. This overrides the specified machine readable format.

 
 

-* `polygon_geojson=1`
-    * Output geometry of results in geojson format.
+* `viewbox=<x1>,<y1>,<x2>,<y2>`

 
 

-* `polygon_kml=1`
-    * Output geometry of results in kml format.
+The preferred area to find search results. Any two corner points of the box
+are accepted as long as they span a real box. `x` is longitude,
+`y` is latitude.

 
 

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

 
 

+* `bounded=[0|1]`
+
+When a viewbox is given, restrict the result to items contained within that
+viewbox (see above). When `viewbox` and `bounded=1` are given, an amenity
+only search is allowed. Give the special keyword for the amenity in square
+brackets, e.g. `[pub]` and a selection of objects of this type is returned.
+There is no guarantee that the result is complete. (Default: 0)
+
+
+### Polygon output
+
+* `polygon_geojson=1`
+* `polygon_kml=1`
+* `polygon_svg=1`

 * `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

 
 

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

 
 

-### Examples
+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.

 
 

+* `dedupe=[0|1]`
+
+Sometimes you have several objects in OSM identifying the same place or
+object in reality. The simplest case is a street being split into many
+different OSM ways due to different characteristics. Nominatim will
+attempt to detect such duplicates and only return one match unless
+this parameter is set to 0. (Default: 1)
+
+* `debug=[0|1]`

 
 

-##### XML with polygon points
+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)

 
 

-* [https://nominatim.openstreetmap.org/search?q=135+pilkington+avenue,+birmingham&format=xml&polygon=1&addressdetails=1](https://nominatim.openstreetmap.org/search?q=135+pilkington+avenue,+birmingham&format=xml&polygon=1&addressdetails=1)
-* [https://nominatim.openstreetmap.org/search/gb/birmingham/pilkington%20avenue/135?format=xml&polygon=1&addressdetails=1](https://nominatim.openstreetmap.org/search/gb/birmingham/pilkington%20avenue/135?format=xml&polygon=1&addressdetails=1)
-* [https://nominatim.openstreetmap.org/search/135%20pilkington%20avenue,%20birmingham?format=xml&polygon=1&addressdetails=1](https://nominatim.openstreetmap.org/search/135%20pilkington%20avenue,%20birmingham?format=xml&polygon=1&addressdetails=1)
+
+
+## Examples
+
+
+##### XML with kml polygon
+
+* [https://nominatim.openstreetmap.org/search?q=135+pilkington+avenue,+birmingham&format=xml&polygon_geojson=1&addressdetails=1](https://nominatim.openstreetmap.org/search?q=135+pilkington+avenue,+birmingham&format=xml&polygon_geojson=1&addressdetails=1)

 
 ```xml
   <searchresults timestamp="Sat, 07 Nov 09 14:42:10 +0000" querystring="135 pilkington, avenue birmingham" polygon="true">
 
 ```xml
   <searchresults timestamp="Sat, 07 Nov 09 14:42:10 +0000" querystring="135 pilkington, avenue birmingham" polygon="true">

-    <place 
-      place_id="1620612" osm_type="node" osm_id="452010817" 
-      boundingbox="52.548641204834,52.5488433837891,-1.81612110137939,-1.81592094898224" 
-      polygonpoints="[['-1.81592098644987','52.5487429714954'],['-1.81592290792183','52.5487234624632'],...]" 
-      lat="52.5487429714954" lon="-1.81602098644987" 
-      display_name="135, Pilkington Avenue, Wylde Green, City of Birmingham, West Midlands (county), B72, United Kingdom" 
+    <place
+      place_id="1620612" osm_type="node" osm_id="452010817"
+      boundingbox="52.548641204834,52.5488433837891,-1.81612110137939,-1.81592094898224"
+      lat="52.5487429714954" lon="-1.81602098644987"
+      display_name="135, Pilkington Avenue, Wylde Green, City of Birmingham, West Midlands (county), B72, United Kingdom"

       class="place" type="house">
       class="place" type="house">

+      <geokml>
+        <Polygon>
+          <outerBoundaryIs>
+            <LinearRing>
+              <coordinates>-1.816513,52.548756599999997 -1.816434,52.548747300000002 -1.816429,52.5487629 -1.8163717,52.548756099999999 -1.8163464,52.548834599999999 -1.8164599,52.548848100000001 -1.8164685,52.5488213 -1.8164913,52.548824000000003 -1.816513,52.548756599999997</coordinates>
+            </LinearRing>
+          </outerBoundaryIs>
+        </Polygon>
+      </geokml>

       <house_number>135</house_number>
       <road>Pilkington Avenue</road>
       <village>Wylde Green</village>
       <house_number>135</house_number>
       <road>Pilkington Avenue</road>
       <village>Wylde Green</village>


@@ -192,7 +250,7 @@ Structured requests are faster and require fewer server resources. **Do not comb
 
 ##### JSON with address details
 
 
 ##### JSON with address details
 

-[https://nominatim.openstreetmap.org/?format=json&addressdetails=1&q=bakery+in+berlin+wedding&format=json&limit=1](https://nominatim.openstreetmap.org/?format=json&addressdetails=1&q=bakery+in+berlin+wedding&format=json&limit=1)
+[https://nominatim.openstreetmap.org/?addressdetails=1&q=bakery+in+berlin+wedding&format=json&limit=1](https://nominatim.openstreetmap.org/?addressdetails=1&q=bakery+in+berlin+wedding&format=json&limit=1)

 
 ```json
     {
 
 ```json
     {


@@ -301,4 +359,4 @@ Structured requests are faster and require fewer server resources. **Do not comb
     }
   ]
 }
     }
   ]
 }

-```
\ No newline at end of file
+```