Prototype — Equal Arc overlay concept

← Live demonstrations · Back to the review · stylized recreation of his Equal Arc Flight (N/S) (Mirror lat) demo with our overlay layer

Review overlay
Author's framing: "Equal arc → equal time, regardless of projection distortion."   ·   What this hides: the southern arc is drawn 2.70× longer in disc units than its lat-mirrored northern partner. Both planes finish in the same wall-clock time only because the demo drives them with a single normalized progress tween — not because the disc says they covered equal distance.
Johannesburg ↔ Sydney · 99.14°
Takeoff00:00:00
Arrival11:00:00
Speed9° 00' 49"/h
Traversed0.00°
Elapsed00:00:00
N-Mirror "≈ Egypt" ↔ "≈ Pacific" · 99.14°
Takeoff00:00:00
Arrival11:00:00
Speed9° 00' 49"/h
Traversed0.00°
Elapsed00:00:00
Race lanes (proportional to AE-projected arc length)
Disc-arc length South arc: 1.627 disc-units
Drawn from JNB (–26°, 28°) to Sydney (–34°, 151°) through his canonical AE projection.
Disc-arc length North arc: 0.602 disc-units
Synthetic lat-mirror endpoints (≈ Egypt + N. Pacific). Same central angle as the south leg by construction.
Sphere theorem Both legs share the same central angle (99.14°). True on a sphere by lat-mirror symmetry. Not a flat-earth result.
Self-contradiction Race lanes are scaled to AE-projected arc length. Both planes finish at the same wall-clock time. South plane covers 2.70× more pixels per second than the north plane. That ratio is the contradiction.
Airline data says Both legs at ~500 mph in the bundled QF27/28 KMZ. On a globe, equal arc → equal time at equal speed. On his disc, equal time on unequal arcs → unequal speed — but he doesn't display speeds in mph, so the contradiction is hidden.
Speed: 1.0× Animation loops every ~11 s @ 1.0× — same cadence as his demo.

What you're looking at

Above is a stylized recreation of the subject model's Equal Arc Flight (N/S) (Mirror lat) demo, with our review layer (red callouts) overlaid on top. The dark-themed scene is a faithful reproduction of his AE disc rendering, his orange/cyan color palette, his info-box HUD layout, and his race-panel widget. The underlying numbers — 1.627 disc-units, 0.602 disc-units, the 2.70× ratio — are computed from his own published functions (greatCircleArc + aeProject in js/data/flightRoutes.js and js/core/canonical.js) against his own city coordinates.

The point of the prototype

This is a visual mockup of the "fork his site, layer overlay annotations on top" approach we considered. Two practical constraints made a true iframe-overlay implausible: cross-origin restrictions block our hosted page from reading state out of his GitHub-Pages-served sim, and his repo carries no LICENSE file, so direct fork-and-modify has unclear footing. The overlay layer you see above does not require either — it overlays a stylized stand-in of his scene with the same review annotations the real-iframe version would carry.

Three options for the production version

  • Iframe-his-site. Embed alanspaceaudits.github.io directly, position our callouts around the iframe edges. We can deep-link to the Equal Arc demo via his URL hash. Limitations: cross-origin blocks state-tracking, so callouts have to be either statically positioned (point at fixed UI elements) or driven by a separate timer that we sync to his autoplay cadence.
  • Snapshot-and-overlay. Capture a high-res screenshot of his demo at a representative moment, layer our callouts as absolutely-positioned HTML on top. Static, but pixel-perfect. Quickest to ship, no live behavior to debug. Re-shoot when his upstream changes.
  • SVG recreation (the current prototype). Reproduce his scene in our own SVG with his colors and proportions. Editable, animatable, version-controlled. No copyright concern. Loses some fidelity vs. a real screenshot of his sim.

The numbers, sourced live

South leg (real) Johannesburg ↔ Sydney
99.14° central angle · 1.627 disc-units
North leg (synthetic mirror) ≈ Egypt ↔ ≈ Pacific
99.14° central angle · 0.602 disc-units
Disc-arc length ratio 2.700×
Implied speed ratio if disc is territory 2.700× (south plane)

Tell me what to change

A few choices to weigh:

  • The callout style — currently red-bordered cards with red dashed connectors to scene features. Could be lighter/quieter, or differently colored per finding category.
  • The animation cadence — currently ~11 s per loop, matching his "11 hours notional flight" tween. Could go faster or slower; could also stop on the contradiction (south plane finishing while north is still mid-arc) for a clear shot.
  • Whether to include the "Airline data says ~500 mph" callout, or pull it into a separate row below the stage. It's the strongest single fact and currently it's overlapping a busy area.
  • Whether to embed his actual site in an iframe below the SVG mockup, side-by-side, so the reader can see they're not the same — i.e., we're presenting a stylized recreation, not a screenshot.