# Feature

## GET /collections/{collectionId}/items/{featureId}

> Retrieve a feature from the feature collection

```json
{"openapi":"3.0.1","info":{"title":"OS NGD API – Features","version":"v1.8.0"},"tags":[{"name":"Features","description":"Retrieve features"}],"servers":[{"url":"https://api.os.uk/features/ngd/ofa/v1"}],"security":[{"api-key":[],"api-key-header":[],"oauth2":[]}],"components":{"securitySchemes":{"api-key":{"type":"apiKey","name":"key","in":"query"}},"schemas":{"Feature":{"type":"object","properties":{"id":{"type":"string"},"type":{"type":"string"},"geometry":{"$ref":"#/components/schemas/Geometry"},"properties":{"type":"object","additionalProperties":{"type":"object"}}}},"Geometry":{"type":"object","properties":{"type":{"type":"string"},"coordinates":{"type":"array","items":{"$ref":"#/components/schemas/Coordinate"}}}},"Coordinate":{"type":"object","properties":{"x":{"type":"number","format":"double"},"y":{"type":"number","format":"double"}}}}},"paths":{"/collections/{collectionId}/items/{featureId}":{"get":{"tags":["Features"],"summary":"Retrieve a feature from the feature collection","operationId":"getItemById","parameters":[{"name":"collectionId","in":"path","description":"A known collection ID.","required":true,"schema":{"type":"string","enum":["asu-gbpcd-postcodeunitarea-1","asu-gbpcd-postcodeunitpoint-1","bld-fts-building-1","bld-fts-building-2","bld-fts-building-3","bld-fts-building-4","bld-fts-buildingaccesslocation-1","bld-fts-buildingline-1","bld-fts-buildingpart-1","bld-fts-buildingpart-2","gnm-fts-crowdsourcednamepoint-1","gnm-fts-namedarea-1","gnm-fts-namedpoint-1","gnm-fts-namedroadjunction-1","lnd-fts-land-1","lnd-fts-land-2","lnd-fts-land-3","lnd-fts-landform-1","lnd-fts-landformline-1","lnd-fts-landformpoint-1","lnd-fts-landpoint-1","lus-fts-site-1","lus-fts-site-2","lus-fts-siteaccesslocation-1","lus-fts-siteaccesslocation-2","lus-fts-siteroutingpoint-1","str-fts-compoundstructure-1","str-fts-compoundstructure-2","str-fts-compoundstructure-3","str-fts-fieldboundary-1","str-fts-structure-1","str-fts-structure-2","str-fts-structure-3","str-fts-structureline-1","str-fts-structurepoint-1","trn-fts-cartographicraildetail-1","trn-fts-rail-1","trn-fts-rail-2","trn-fts-rail-3","trn-fts-roadline-1","trn-fts-roadtrackorpath-1","trn-fts-roadtrackorpath-2","trn-fts-roadtrackorpath-3","trn-fts-streetlight-1","trn-ntwk-buslane-1","trn-ntwk-connectinglink-1","trn-ntwk-connectingnode-1","trn-ntwk-cyclelane-1","trn-ntwk-ferrylink-1","trn-ntwk-ferrynode-1","trn-ntwk-ferryterminal-1","trn-ntwk-path-1","trn-ntwk-pathlink-1","trn-ntwk-pathlink-2","trn-ntwk-pathlink-3","trn-ntwk-pathnode-1","trn-ntwk-pavementlink-1","trn-ntwk-railwaylink-1","trn-ntwk-railwaylinkset-1","trn-ntwk-railwaynode-1","trn-ntwk-road-1","trn-ntwk-roadjunction-1","trn-ntwk-roadlink-1","trn-ntwk-roadlink-2","trn-ntwk-roadlink-3","trn-ntwk-roadlink-4","trn-ntwk-roadlink-5","trn-ntwk-roadnode-1","trn-ntwk-street-1","trn-ntwk-tramonroad-1","trn-rami-averageandindicativespeed-1","trn-rami-highwaydedication-1","trn-rami-maintenancearea-1","trn-rami-maintenanceline-1","trn-rami-maintenancepoint-1","trn-rami-reinstatementarea-1","trn-rami-reinstatementline-1","trn-rami-reinstatementpoint-1","trn-rami-restriction-1","trn-rami-routinghazard-1","trn-rami-routingstructure-1","trn-rami-specialdesignationarea-1","trn-rami-specialdesignationline-1","trn-rami-specialdesignationpoint-1","wtr-fts-intertidalline-1","wtr-fts-tidalboundary-1","wtr-fts-water-1","wtr-fts-water-2","wtr-fts-water-3","wtr-fts-waterpoint-1","wtr-ntwk-waterlink-1","wtr-ntwk-waterlink-2","wtr-ntwk-waterlinkset-1","wtr-ntwk-waternode-1"]}},{"name":"featureId","in":"path","description":"A feature ID which is the identifier(id) for the feature.","required":true,"schema":{"type":"string"}},{"name":"crs","in":"query","description":"The coordinate reference system of the response geometries. It must be a coordinate reference system supported by the collection. Default is WGS84 longitude/latitude (http://www.opengis.net/def/crs/OGC/1.3/CRS84).","schema":{"type":"string","enum":["http://www.opengis.net/def/crs/OGC/1.3/CRS84","http://www.opengis.net/def/crs/EPSG/0/27700","http://www.opengis.net/def/crs/EPSG/0/4326","http://www.opengis.net/def/crs/EPSG/0/3857","http://www.opengis.net/def/crs/EPSG/0/7405"]}}],"responses":{"200":{"description":"A single feature in the feature collection.","content":{"application/geo+json":{"schema":{"$ref":"#/components/schemas/Feature"}}}},"400":{"description":"The feature request contains elements that are not supported. Please refer to documentation for examples."},"404":{"description":"The feature collection '{collectionId}' or feature with id:'{featureId}' could not be found. Please check it is a supported collection or feature."},"405":{"description":"The HTTP method requested is not supported. This endpoint only supports 'GET' requests."},"406":{"description":"A request header value was not supported."},"504":{"description":"The request has timed out. Please check the service availability dashboard: https://osdatahub.os.uk/serviceStatus ."}}}}}}
```


---

# Agent Instructions: 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:

```
GET https://docs.os.uk/os-apis/accessing-os-apis/os-ngd-api-features/technical-specification/feature.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
