Civil
Established territorial timekeeping from mapped boundary evidence.
SPATIAL TIME REFERENCE
GeoTZ 0.1
A deterministic spatial companion to IANA tzdb 2026c: one explainable time assignment for every valid coordinate on Earth.
THE CONTRACT
Time without unknown surface
Every WGS 84 coordinate resolves to a canonical IANA or fixed-offset identifier, a place classification, an assignment basis, an evidence class, and a stable authority decision.
Maritime
Conventional high-seas time, including documented date-line extensions.
Operational
Documented facility clocks expressed as explicit local time enclaves.
Derived
Published GeoTZ rules where neither civil nor operational authority owns the assignment.
WHY IT EXISTS
IANA defines clock rules. GeoTZ makes spatial decisions explicit.
IANA tzdb is the temporal authority used by GeoTZ. It supplies histories, transitions, identifiers, and representative locations. It does not publish a complete global polygon partition. GeoTZ does not replace or modify IANA.
GeoTZ adds a versioned spatial contract: precedence, exact-boundary behavior, polar convergence, international-water conventions, provenance, evidence labels, and reproducible validation.
REFERENCE CASE
Antarctica: continuity plus time enclaves
Unassigned Antarctic surface continues adjacent fixed-offset maritime bands. Documented station clocks override that surface only inside clearly labelled 25 km derived time enclaves. These are operational conventions, never territorial claims.
REPRODUCE AND CHALLENGE IT
Reference artifacts
- Polished technical preprintPeer-review-oriented paper with formal model, evidence, evaluation, and limitations
- LaTeX submission sourceEditable manuscript, BibTeX references, and build guidance
- Normative JSON SchemaAuthority structure and vocabulary
- Reference generatorDeterministic build source
- Adversarial test vectorsPoles, antimeridian, date shifts, borders, and enclaves
- Independent verifierStandalone decision-path check
- Dense audit result259,200 global probes plus structural checks
- Versioned manifestSources, hashes, scope, and compatibility
Scope and attribution
GeoTZ 0.1 is an experimental reference implementation, not a legal boundary source, sovereignty claim, maritime regulation, or IANA publication. It is compatible with IANA tzdb 2026c.
Mapped timezone information derives from Timezone Boundary Builder 2026c, available under the Open Database License 1.0. Antarctic land geometry is made with Natural Earth, public domain. GeoJSON follows RFC 7946.