Inspector Walls prepared flight database — format and reuse guide I prepare the recorded-flight figures at public geographic grid points before a listing is opened. The card uses the nearest compatible point and shows its distance from the listing pin. This download contains the complete published annual summaries, including their daily counts, and the grid geometry. Start with /data/aircraft-spatial/manifest.json. Keep its version query when following tile links: it selects one immutable publication. Each download has a byte length and SHA-256 checksum. The sourceEvidence link gives the retained flight observations and derived trajectories used for this publication. File formats ------------ All multi-byte numbers in the binary files are little-endian. Tile ordinals and row ordinals start at zero. Each tile has three files: geometry.json.gz: gzip-compressed UTF-8 JSON array, one cell per row ordinal. Each cell has key, bounds, home and maximumOffsetM. Coordinates are WGS84 latitude/longitude in degrees. Bounds are west/east/south/north. The home is a public lattice centre, not a user or listing location. Heights are metres; heightDatum is ODN, Belfast or null. Missing heights remain null. The SHA-256 of the uncompressed array equals gridSha256. maximumOffsetM is the greatest permitted horizontal displacement; a particular query also needs matching terrain, datum availability and original 0.01-degree terrain parent. annual-records.bin: a sequence of frames. Each frame begins with a 4-byte unsigned row ordinal and a 4-byte unsigned compressed-payload length, followed by exactly that many bytes of gzip-compressed UTF-8 JSON. That JSON is the complete annual tracks summary, including the daily counts and quality fields. Frame order need not equal row order. Use the ordinal, not the frame position. ordinal-index.bin: exactly 12 bytes per geometry row, in row-ordinal order. The first 8 bytes are a Float64 byte offset of the compressed payload in annual-records.bin; the last 4 bytes are its unsigned compressed length. The matching 8-byte frame header is immediately before the payload offset. Offsets are integral and exactly representable. Confirm its ordinal and length before decoding a record. The index is a convenience; all rows can also be recovered by scanning the framed records. Geometry, annual records and their index must come from the same manifest tile. homes is a count of prepared grid points, not a count of properties. planSha256, gridSha256 and the three producer hashes bind the preparation inputs and code. contentSha256 binds the canonical online geometry and annual summary content; the online projection omits only daily rows. File SHA-256 values independently bind the full exported bytes. Internal public-offer receipts use JSON with recursively sorted object keys, unchanged array order and one trailing newline. Public manifest links replace private storage references with public routes. Meaning and limits ----------------- I count separate recorded close approaches within 3 km using position and height together, under the calculationVersion in the manifest. Daily counts are divided by eligible recorded days. Missing dates are not zero-flight days. Pressure-only heights remain uncertain. Local receiver completeness is unmeasured; a zero count does not prove a quiet sky. These figures describe recorded aircraft approaches, not indoor sound measurements. Spatial estimates can differ at a nearby point, especially at an encounter or height-band boundary. The source can contain contradictory observations; I retain the model's quality information. No inspection history, user submissions or listing pins are in this public download. Licence and credits ------------------- Contains information from ADSB.lol, made available under the Open Database License (ODbL). https://opendatacommons.org/licenses/odbl/1-0/ Source: https://www.adsb.lol/docs/open-data/historical/ I offer the prepared derivative database under that same ODbL licence. Keep these credits and the applicable licence notices when reusing it. Contains Ordnance Survey data © Crown copyright and database right 2026. Contains public sector information licensed under the Open Government Licence v3.0. https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Geometry sources: OS Open UPRN, OS Code-Point Open, OS Terrain 50, OSNI Open Data 50m DTM, and NISRA Census 2021 occupied households. The manifest retains the bound source names and available official URLs. Derived from work by Ordnance Survey. GeoTIFF conversion by the PROJ-data project. https://cdn.proj.org/uk_os_README.txt The geoid conversion's complete BSD notice follows, unchanged: Scoped-area publications ------------------------ A manifest with schema aircraft-spatial-area-public-offer-v1 describes one prepared area and explicitly sets nationalCoverage to false. Its tiles array contains the complete loaded annual tile. candidates.geometry links the complete public lattice geometry for the represented terrain parents, including nearby competitors whose annual summaries are not loaded. These are public grid centres, not property identities, addresses, listing pins or user inspection history. Rank the complete candidate set with the same terrain, bounds, distance and tie-break rules before looking up the annual row. If the best compatible key does not occur in the loaded tile, the query is outside this prepared area; do not substitute a farther loaded key. The candidate array has no annual rows and its array positions must not be used in the loaded tile's ordinal index. For scoped-area geometry, uncompressedSha256 binds the exact downloaded JSON bytes. It need not equal original gridSha256 because projected object-key order may differ. geometrySha256 and candidate contentSha256 use the area definition's logical geometry digest: in sorted unique key order, hash each recursively key-sorted geometry object (without newline), append key, a NUL, that hex hash and a newline to the aggregate SHA-256. The annual index still refers to the loaded geometry array order. Keep sourceManifestSha256, areaDefinitionSha256, originalPlan and all file hashes together. Neither the area schema nor a downloadable bundle claims national coverage or national accuracy acceptance. Additional prepared areas ------------------------- /data/aircraft-spatial/areas.json lists separately published complete areas. London's three tiles share one generation and each links to its own versioned manifest. The default manifest.json remains the original prepared publication. London's original national atlas and its three-tile preparation have separate checksums. Its 157,997 candidate points preserve complete original parents; only original listing pins inside the bound London borough polygons are served. Candidate coordinates outside that polygon do not extend the listing coverage. Derived from work by Ordnance Survey. The 2-Clause BSD License: https://opensource.org/license/bsd-2-clause Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.