What you are looking at

Substrate. Every mark, callsign and the frame's own baked HUD arrive as raw RGBA from the cell. SHA-256 is recomputed in this tab and compared to X-Gop-Digest before the frame is drawn. A mismatch, or a byte length that disagrees with the declared geometry, refuses the frame outright.

Decoration. The backdrop image, the degree graticule and the vignette. They are drawn under and over the verified bytes — never into them. Press Substrate only to strip all of it and see the verified pixels.

Honest limits

No video model. Frames are the substrate's state under a vantage, not imagined motion. Nothing is generated ahead of time, which is what makes it live.

The backdrop is not the map. It is a fixed photographic plate behind the frame, chosen by stance and zoom. It does not pan, it does not scale with the vantage, and it encodes no geography — because a backdrop that appeared to move with the data would be a rendering impersonating a fact. Only the graticule and the marks carry coordinates.

A third plate was built and cut. A photoreal coastline was generated and wired in. Driven at 42.91°N 57.49°W — open ocean — it sat under the degree grid and read as the terrain at those coordinates. It was labelled correctly and the label did not help: the picture itself was making the claim. Only plates that cannot be mistaken for a map of anywhere ship — the earth's limb from orbit, and cloud over water.

Heading does nothing. azimuth_milli is parsed by the route but does not change the frame, so no heading control is offered rather than shipping a dial that lies.

The frame lags your hand. A frame costs the cell about 2.2–2.7 s to rasterise at any size in this range, so while you drag or zoom the last verified frame is shown transformed into the new vantage and marked STALE. Nothing is re-verified until the real frame for that vantage arrives.

The composite is not reproducible; the substrate is. Hashing this canvas after each repaint, Substrate only returns the same SHA-256 every time and it equals the digest the cell served. The composited picture does not: the browser's blur rasteriser settles on one of two results depending on whether the canvas is GPU- or CPU-backed at that moment. That is the whole argument for checking the hash on the raw bytes before compositing, and for keeping a button that strips the decoration away.

Frame rate is state-driven. A still world produces a still frame; a rate target would only reward redrawing nothing.

Live Twin

Real air traffic, weather and water — rasterised as integers by the cell, verified in your browser before a pixel is drawn, no GPU anywhere.

VERIFYING PAUSED marks — — × — gpu — — fetch SUBSTRATE + DECOR substrate · verified RGBA · decoration · drawn around it · drag to move · wheel to zoom at cursor