Boundr - UK Boundary Data

List Boundary Type Codes

Returns every valid UK boundary type code mapped to its human-readable label. Call this before using any tool that accepts a `boundary_type` or `boundary_types` argument so you know which codes are legal. Passing an unlisted code to another tool raises a ValueError. Boundary type codes are stable Ordnance Survey identifiers. Common ones: - "CTY" → County - "LBO" → London Borough - "UTA" → Unitary Authority - "MTD" → Metropolitan District - "DIS" → District - "DIW" → District Ward - "CCTY

Search Boundaries By Name

Search for UK administrative boundaries by name (case-insensitive partial match). Use this to discover boundaries when you have a place name but not a code. Returns lightweight metadata only — no geometry. If you need to display or analyse the boundary shape, call get_boundary_geojson_by_code() with the returned `code`. Call list_boundary_type_codes() first if you need to filter by type and are unsure which code to use.

Find Boundaries At Point

Find all UK administrative boundaries that geographically contain a coordinate point. Use this to answer "what county/borough/ward is this location in?" for a latitude/longitude. Returns lightweight metadata only — no geometry. If you need to display a boundary shape, call get_boundary_geojson_by_code() with the returned `code`. Multiple boundaries at different administrative levels typically contain the same point (e.g. a ward, a borough, and a county). Filter by boundary_types to restrict wh

Get Boundary By Code

Look up metadata for a single UK boundary by its ONS census code. No geometry. Use this when you already have a census code (e.g. from search_boundaries_by_name() or find_boundaries_at_point()) and need structured metadata such as area size or type label. If you also need the boundary shape for display or analysis, call get_boundary_geojson_by_code() instead. ONS census codes (sometimes called GSS codes or LAU codes) are stable identifiers of the form "E09000012" (Hackney), "E10000016" (Kent),

Get Boundary Geojson By Code

Fetch the full GeoJSON geometry for a UK boundary by its ONS census code. Returns a GeoJSON Feature object (WGS-84 / EPSG:4326) suitable for rendering on a map or performing geometric analysis. The geometry can be large — county and ceremonial county polygons are especially heavy. Only call this when you specifically need the shape; for metadata only use get_boundary_by_code() instead. IMPORTANT — Leaflet / web maps: use get_boundary_geojson_simplified() instead. The full geometry is large eno

Get Boundary Geojson Simplified

Fetch simplified GeoJSON for a boundary by its ONS census code. Safe to embed directly in generated HTML map files. At the default tolerance (0.0001°) a constituency polygon shrinks from ~4,000 vertices to ~200–400 with no visible difference at normal map zoom levels. Prefer this over get_boundary_geojson_by_code() when writing Leaflet map pages — the full geometry is large enough to exhaust your context window before you can finish writing the HTML.

Get Boundary Bbox

Get the bounding box and centroid for a boundary by its ONS census code. Returns min_lat, max_lat, min_lng, max_lng, centroid_lat, centroid_lng. Pass the bbox values directly to Knotsure's sightings_in_bbox() or geographic_summary(). Much cheaper than get_boundary_geojson_by_code() for spatial queries because no geometry is fetched or serialised.