open-standards/map/vocab/LEXICON.md

Map lexicon (v1)

The controlled vocabulary of the Map standard. Terms are stable; their IRIs live in v1.ttl under https://maps.transaction.science/vocab/v1#.

Term	Meaning
Place	The cargo Map carries: a region of the world at a position, altitude, instant, and fidelity.
Tile	A content-addressed, signed unit of place at a single cell, with its energy cost intrinsic. The unit of cargo.
Cell key	The 4D address of a tile: (s2, alt, time, lod).
S2 cell	The horizontal axis: a hierarchical, Hilbert-ordered cell on the sphere. Its level is the horizontal LOD.
Altitude band	The vertical axis: a signed band index against the tileset's declared schedule. Band 0 = datum.
Time bucket	The temporal axis: a half-open [start, start+width) TAI interval. Bucket 0 = atemporal. First-class.
LOD	The within-tier detail level, independent of the S2 level.
Content id	blake3(canonical_cbor(x)) — the 32-byte address every structure cross-references through.
Tileset	The single range-requestable archive: header + Hilbert-ordered directory + payloads. "It's just a file."
Directory	The CellKey → (offset, len, content_id) map, sorted by the S2 key so a viewport is a near-contiguous byte range.
Manifest	The signed root of a tileset; commits to the directory Merkle root under a publisher key.
Revision	A signed, dated transition prev_root → new_root. Append-only; a new forecast hour / AIRAC cycle is a revision.
Fidelity cascade	F0:Cache → F1:Base → F2:Field → F3:Feature → F4:Photoreal. The highest tier ≤ the request that holds data closes it.
Base floor	F1 — terrain + coastlines + borders, defined everywhere; the guaranteed fallback.
Receipt	The signed per-resolve energy record (measured + estimated µJ, provenance-tagged), sealed as JCR-1.
Provenance	HwShunt (hardware-measured) | ModelBased (calibrated model) | Estimator (constant). The honesty tag on every reading.
Steward	Transaction Science: publishes the spec, ships the reference, runs optional services. Not the owner — Map carries no token.