UK Data AtlasAPI

List a named location's areas

List the areas that make up a named location in a boundary release you choose, such as the wards of North Wales. Anything that can't be matched is listed too, with the reason.

get
/locations/{location-id}/members

Good to know

  • Named locations are made of local authorities. For any other geography, name a crosswalk with via.

Path parameters

  • location-idstringrequired

    A curated named location id from GET /v1/locations, e.g. greater-manchester.

Query parameters

  • geographystringoptional

    The geography to resolve members in. Omit it to use the location's declared memberGeography; any other geography requires via.

  • releasestringrequired

    The boundary release to resolve members in, which fixes the vintage of the codes returned.

  • viastringoptional

    The published crosswalk to resolve through, required for any geography other than the location's memberGeography. Omit it to be told which are available.

  • asOfstringoptional

    Select member codes effective on this date. Date selection is currently available for direct member-code matches only, not a crosswalk projection.

Returns

object

Resolved members, explicitly unresolved codes, and the coverage that explains each one.

When it goes wrong

  • 400release is missing, or a geography other than the location's memberGeography was asked for without via. The detail lists the crosswalks published for that geography and release.
  • 404No resource matches that identity.

Every error has the same shape. See Errors for how to handle them.

Technical notes

Show the precise behaviour

release is required because location definitions may include legacy codes. Missing members are returned explicitly; this route never applies an implicit historical conversion. A coverage object counts resolved and unresolved members and classifies each unresolved code against the compiled releases of its geography as superseded, not-yet-current, absent-from-release or unknown, naming the releases that are the evidence. The classification is relative to the requested release and reports code membership only; it asserts nothing about geometry.

A location declares the geography of its member codes, so asking for that geography matches them directly and membership is direct-code-match. Any other geography has to be reached through a published crosswalk, named with via: the wards of North Wales, the constituencies of Merseyside. Asking without via returns a 400 that lists the crosswalks published for that geography and release, so the choice is the caller's and is made from what exists.

What membership means depends on the crosswalk named, and the response says which. Through a clean-containment crosswalk it is fully-contained: the publisher places each area wholly inside one parent, so no area is counted in part. Through an area-overlap crosswalk it is weighted-overlap: an area straddling the edge of the location carries the weight lying inside and is marked partial, and partialMembers counts them. Shares in two members of the same location are added, so an area split between them is whole and not partial.

Each member names the defining area it was found through, and parentBoundaryRelease names the release the location's own codes were resolved against, which is the release the crosswalk ends at rather than the one asked for. Each member's relation is within when the whole area lies inside the location and partly-within when only its weight does; only the first may be counted whole.

reach says which of the location's authorities the crosswalk places any area under. A crosswalk covering fewer countries than the location spans, such as LSOAs for a Scottish city, leaves authorities in unreached, and the members under them are missing from the answer rather than absent from the ground.