> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-apis/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-apis/accessing-os-apis/os-places-api/technical-specification/polygon.md).

# Polygon

{% hint style="warning" %}

### API test authentication

The Open API block allows you to test OS APIs directly from the page with example data and parameters. To use this feature, you will need to add your API Key or OAuth2 token to the authentication field.

For help generating an API Key or OAuth2 token, please see the [Getting started with an API project](https://docs.os.uk/os-apis/core-concepts/getting-started-with-an-api-project) or [OAuth2 documentation](https://docs.os.uk/os-apis/accessing-os-apis/oauth-2-api).
{% endhint %}

## POST /polygon

> Returns matched addresses within a geoJSON polygon or multi-polygon object.

```json
{"openapi":"3.0.1","info":{"title":"OS Places API","version":"v1.0"},"tags":[{"name":"Polygon","description":"Find all addresses in a polygon or multi-polygon object."}],"servers":[{"url":"https://api.os.uk/search/places/v1"}],"security":[{"api-key":[],"api-key-header":[],"oauth2":[]}],"components":{"securitySchemes":{"api-key":{"type":"apiKey","name":"key","in":"query"}},"schemas":{"SearchResult":{"type":"object","properties":{"header":{"type":"object","properties":{"uri":{"type":"string"},"query":{"type":"string"},"offset":{"type":"integer"},"totalresults":{"type":"integer"},"format":{"type":"string"},"dataset":{"type":"string"},"lr":{"type":"string"},"maxresults":{"type":"integer"},"matchprecision":{"type":"integer"},"epoch":{"type":"string"},"lastupdate":{"type":"string"},"output_srs":{"type":"string"}},"required":["uri","query","offset","totalresults","format","dataset","lr","maxresults","matchprecision","epoch","lastupdate","output_srs"]},"results":{"type":"array","items":{"type":"object","properties":{"DPA":{"$ref":"#/components/schemas/DPA"},"LPI":{"$ref":"#/components/schemas/LPI"}}}}}},"DPA":{"type":"object","properties":{"UPRN":{"type":"string"},"UDPRN":{"type":"string"},"ADDRESS":{"type":"string"},"ORGANISATION_NAME":{"type":"string"},"DEPARTMENT_NAME":{"type":"string"},"SUB_BUILDING_NAME":{"type":"string"},"BUILDING_NAME":{"type":"string"},"BUILDING_NUMBER":{"type":"string"},"DEPENDENT_THOROUGHFARE_NAME":{"type":"string"},"THOROUGHFARE_NAME":{"type":"string"},"DOUBLE_DEPENDENT_LOCALITY":{"type":"string"},"DEPENDENT_LOCALITY":{"type":"string"},"POST_TOWN":{"type":"string"},"POSTCODE":{"type":"string"},"RPC":{"type":"string"},"X_COORDINATE":{"type":"number"},"Y_COORDINATE":{"type":"number"},"LNG":{"type":"number"},"LAT":{"type":"number"},"STATUS":{"type":"string"},"LOGICAL_STATUS_CODE":{"type":"string"},"CLASSIFICATION_CODE":{"type":"string"},"CLASSIFICATION_CODE_DESCRIPTION":{"type":"string"},"LOCAL_CUSTODIAN_CODE":{"type":"integer"},"LOCAL_CUSTODIAN_CODE_DESCRIPTION":{"type":"string"},"COUNTRY_CODE":{"type":"string"},"COUNTRY_CODE_DESCRIPTION":{"type":"string"},"POSTAL_ADDRESS_CODE":{"type":"string"},"POSTAL_ADDRESS_CODE_DESCRIPTION":{"type":"string"},"BLPU_STATE_CODE":{"type":"string"},"BLPU_STATE_CODE_DESCRIPTION":{"type":"string"},"TOPOGRAPHY_LAYER_TOID":{"type":"string"},"WARD_CODE":{"type":"string"},"PARISH_CODE":{"type":"string"},"PARENT_UPRN":{"type":"string"},"LAST_UPDATE_DATE":{"type":"string"},"ENTRY_DATE":{"type":"string"},"LEGAL_NAME":{"type":"string"},"BLPU_STATE_DATE":{"type":"string"},"LANGUAGE":{"type":"string"},"MATCH":{"type":"number"},"MATCH_DESCRIPTION":{"type":"string"},"DELIVERY_POINT_SUFFIX":{"type":"string"}}},"LPI":{"type":"object","properties":{"UPRN":{"type":"string"},"ADDRESS":{"type":"string"},"USRN":{"type":"string"},"LPI_KEY":{"type":"string"},"ORGANISATION":{"type":"string"},"SAO_START_NUMBER":{"type":"string"},"SAO_START_SUFFIX":{"type":"string"},"SAO_END_NUMBER":{"type":"string"},"SAO_END_SUFFIX":{"type":"string"},"SAO_TEXT":{"type":"string"},"PAO_START_NUMBER":{"type":"string"},"PAO_START_SUFFIX":{"type":"string"},"PAO_END_NUMBER":{"type":"string"},"PAO_END_SUFFIX":{"type":"string"},"PAO_TEXT":{"type":"string"},"STREET_DESCRIPTION":{"type":"string"},"LOCALITY_NAME":{"type":"string"},"TOWN_NAME":{"type":"string"},"ADMINISTRATIVE_AREA":{"type":"string"},"AREA_NAME":{"type":"string"},"POSTCODE_LOCATOR":{"type":"string"},"RPC":{"type":"string"},"X_COORDINATE":{"type":"number"},"Y_COORDINATE":{"type":"number"},"LNG":{"type":"number"},"LAT":{"type":"number"},"STATUS":{"type":"string"},"LOGICAL_STATUS_CODE":{"type":"string"},"CLASSIFICATION_CODE":{"type":"string"},"CLASSIFICATION_CODE_DESCRIPTION":{"type":"string"},"LOCAL_CUSTODIAN_CODE":{"type":"integer"},"LOCAL_CUSTODIAN_CODE_DESCRIPTION":{"type":"string"},"COUNTRY_CODE":{"type":"string"},"COUNTRY_CODE_DESCRIPTION":{"type":"string"},"POSTAL_ADDRESS_CODE":{"type":"string"},"POSTAL_ADDRESS_CODE_DESCRIPTION":{"type":"string"},"BLPU_STATE_CODE":{"type":"string"},"BLPU_STATE_CODE_DESCRIPTION":{"type":"string"},"TOPOGRAPHY_LAYER_TOID":{"type":"string"},"WARD_CODE":{"type":"string"},"PARISH_CODE":{"type":"string"},"PARENT_UPRN":{"type":"string"},"LAST_UPDATE_DATE":{"type":"string"},"ENTRY_DATE":{"type":"string"},"LEGAL_NAME":{"type":"string"},"BLPU_STATE_DATE":{"type":"string"},"STREET_STATE_CODE":{"type":"string"},"STREET_STATE_CODE_DESCRIPTION":{"type":"string"},"STREET_CLASSIFICATION_CODE":{"type":"string"},"STREET_CLASSIFICATION_CODE_DESCRIPTION":{"type":"string"},"LPI_LOGICAL_STATUS_CODE":{"type":"string"},"LPI_LOGICAL_STATUS_CODE_DESCRIPTION":{"type":"string"},"LANGUAGE":{"type":"string"},"MATCH":{"type":"number"},"MATCH_DESCRIPTION":{"type":"string"}}}}},"paths":{"/polygon":{"post":{"tags":["Polygon"],"summary":"Returns matched addresses within a geoJSON polygon or multi-polygon object.","operationId":"postPolygon","requestBody":{"required":true,"content":{"application/json":{"schema":{"type":"object","properties":{"type":{"type":"string"},"geometry":{"type":"object"}},"required":["type","geometry"]}}}},"parameters":[{"name":"Content-Type","in":"header","description":"The media type of the request body","required":true,"schema":{"type":"string","enum":["application/json"]}},{"name":"referencepoint","in":"query","description":"Reference point geometry is the basis from which the distance value is calculated. Output is ordered by ascending distance from given reference point only if parameter has been specified.","required":false,"schema":{"type":"integer"}},{"name":"maxresults","in":"query","description":"The maximum number of results to return. Default: 100.","required":false,"schema":{"type":"integer","default":"100","minimum":1,"maximum":100}},{"name":"offset","in":"query","description":"Offset the list of returned results by this amount.","required":false,"schema":{"type":"integer","default":"0"}},{"name":"dataset","in":"query","description":"The dataset to return. Multiple values can be sent, separated by a comma. Default: DPA.","required":false,"schema":{"type":"string","default":"DPA","enum":["DPA","LPI"]}},{"name":"lr","in":"query","description":"Which language of addresses to return. Default: EN, CY.","required":false,"schema":{"type":"string","enum":["EN","CY"]}},{"name":"output_srs","in":"query","description":"The intended output spatial reference system. Default: EPSG:27700","required":false,"schema":{"type":"string","default":"EPSG:27700","enum":["BNG","EPSG:27700","WGS84","EPSG:4326","EPSG:3857","EPSG:4258"]}},{"name":"srs","in":"query","description":"The spatial reference system for the input coordinate set.","required":false,"schema":{"type":"string","enum":["BNG","EPSG:27700","WGS84","EPSG:4326","EPSG:3857","EPSG:4258"]}},{"name":"fq","in":"query","description":"Filter for classification code, logical status code, LPI logical status code and/or country code. Filtering for classification code will accept wildcard ( * ) searches. Multiple searches can be done by separating the codes with a space. Multiple filters can be used together by including the parameter multiple times","required":false,"schema":{"type":"array","items":{"type":"string"}}}],"responses":{"200":{"description":"Retrieves matched addresses","content":{"application/json":{"schema":{"$ref":"#/components/schemas/SearchResult"}},"application/xml":{"schema":{"$ref":"#/components/schemas/SearchResult"}}}}}}}}}
```


---

# Agent Instructions
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## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.os.uk/os-apis/accessing-os-apis/os-places-api/technical-specification/polygon.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
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