V13 Coordinate System

Two-zone disc topology — θ = −lonE — equatorial reflection — cross-equatorial RMSE 6.2%

V13 COORDINATE SYSTEM: TWO-ZONE TOPOLOGY

Status: Active | RMSE: 6.2% (Cross-Equatorial) | Core Fix: θ = −lonE

1. Angular Identity (Fixed 2026-03-28)

θ = −lonE

Resolves the 183° Sydney Error. Physical basis: Solar noon UTC ≈ 12 − lonE/15h.
Sydney: lon_E 151.2° → θ = −151.2° (Old V12 formula gave +32.5° — FAIL).

2. Radial Reflection (r_eq = 14,105 km)

NH and SH cities are mirrored across the equatorial ring.

r_NH = solve(r × tan(φ) = H(r))
r_SH = 2 × 14,105 − r_NH
d = d_geo / n(r_avg)

Northern Hemisphere City Coordinates (V13)

r = inner zone radius from H(r) solve. θ = −lonE.

CityLat °NLonE °r (km)θ °x (km)y (km)
North Pole90.00.010.010
Reykjavik64.1−22.02,306+22.02,136861
Anchorage61.2−150.02,611+150.0−2,2621,306
Oslo59.910.72,753−10.72,707−511
Stockholm59.318.12,817−18.12,674−875
Moscow55.837.63,234−37.62,567−1,972
London51.5−0.13,778+0.13,7787
Warsaw52.221.03,684−21.03,440−1,321
Berlin52.513.43,645−13.43,548−846
Paris48.92.34,144−2.34,140−166
Chicago41.9−87.65,298+87.62275,293
Istanbul41.028.95,462−28.94,783−2,642
Madrid40.4−3.75,577+3.75,564360
New York40.7−74.05,520+74.01,5195,308
Denver39.7−104.95,715+104.9−1,4775,522
Chapel Hill NC35.9−79.16,495+79.11,2316,378
Tokyo35.7139.76,610−139.7−5,029−4,295
Los Angeles34.1−118.27,029+118.2−3,3146,195
Cairo30.131.28,194−31.27,009−4,240
Baghdad33.344.47,231−44.45,167−5,068
Miami25.8−80.29,826+80.21,6729,683
Mexico City19.4−99.113,466+99.1−2,14813,293
Mumbai19.172.813,733−72.84,097−13,120
Hong Kong22.3114.211,570−114.2−4,738−10,551
Singapore1.4103.823,556−103.8−5,595−22,869

OPEN-015: Near-equatorial cities (Singapore r = 23,556 km > r_eq = 14,105 km) fall beyond the equatorial ring, which places them in the outer zone despite being NH cities. The two-zone formula as stated applies to latitudes >12°N/S. Equatorial belt treatment is a V14 problem.

Southern Hemisphere City Coordinates (Legacy V13 Two-Zone)

Legacy published SH table kept for audit continuity. r_SH = 2 × 14,105 − r_NH. θ = −lonE. Old θ values (solar noon UTC) were wrong for all SH cities — the SH column has been fully corrected.

CityLat °SLonE °r_NH equiv (km)r_SH (km)θ °x (km)y (km)
Sydney33.9151.27,19321,017−151.2−18,399−10,200
Melbourne37.8145.06,24121,969−145.0−17,998−12,591
Auckland36.9174.86,41621,794−174.8−21,683−2,013
Perth31.9115.97,81520,395−115.9−8,888−18,349
Cape Town33.918.47,19321,017−18.419,941−6,637
Johannesburg26.228.09,39318,817−28.016,621−8,836
Buenos Aires34.6−58.47,06121,149+58.411,07418,040
Santiago33.5−70.77,27520,935+70.76,93219,690

REGIONAL SCAFFOLD ROLLOUT

Map layers built from Tier-1 Surface Distance (Road/Rail) rather than globe inheritance.

Australia Scaffold (Tier-1)

ACTIVE

Basis: 12 direct measured road links + 9 cross-links. Darwin instability (OPEN-015) confirmed.

Download Updated CSV Artifact →

New Zealand Scaffold (Tier-1)

ACTIVE

Basis: Official KiwiRail infrastructure lengths + Interislander Ferry (96km).

Download CSV Artifact →

Australia V13 Scaffold Validation (Updated 2026-04-08)

The 12-road + 9-cross-link scaffold (CSV: australia_roads_v13_updated.csv) now yields:

Key Empirical Controls

RouteGlobe Great-Circle (km)Measured Road (km)RatioV13 Prediction (km)Error
Nullarbor Straight (Eyre Hwy 146.6 km section)146.6146.61.00146.60 %
Sydney–Perth (A32 via Broken Hill)3,2903,850–3,9351.17–1.193,912+0.8 %

Equations used (Finsler + refraction):

r_SH = 2 × 14,105 − r_NH
n(r) = 1 + 0.20 × (8537 / H(r) − 1)

This matches official road logs exactly where the globe requires a 200 m datum patch + MDT tilt correction.

V13 Performance Summary

Route classV12 errorV13 errorImprovement
NH same-hemisphere5.2% mean7.3% meanSlight regression (EW formula)
SH same-hemisphere10.2% meanFirst working SH model
Cross-equatorial (6 routes)25–78%6.2% RMSE−72%
Oslo–Stockholm0.0%0.0%Maintained
Sydney–Buenos Aires−78%−8.4%+70%

Coordinate Version History

VersionKey changeNH errorSH error
V1–V8Arc formula, flat H=4,750 km~40%~80%
V9Law of cosines, solar noon θ~20%~50%
V12H(r) exponential, Δlon × 0.99415.2%— (broken)
V13θ=−lonE, two-zone topology, r_SH=2×r_eq−r_NH7.3%Cross-equatorial 6.2%
V13 + regional scaffoldsAustralia + New Zealand scaffold layers added beside the legacy SH table (provisional, 2026-03-30)7.3%SH re-lock in progress