The Piri Reis Map: Visualisation · Signals from the Periphery

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THE CHART

Projection centre

30.0°N 31.2°E

South-coast fit

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Drake gap

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THE PIRI REIS MAP · THE PROJECTION BENCH
Gallipoli 1513 · Topkapi 1929 · the Antarctica claim
a chart, a projection machine, a coast on trial
distance & bearing held true from one chosen centre
the southern coast: ice-free Antarctica, or a bent Patagonia?
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Feature

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Evidence

fact ⇄ what kind of claim · live

Drawn 1513 at Gallipoli on gazelle skin; rediscovered at Topkapi, autumn 1929

famous first for its Columbus source, not for Antarctica

REPORTED

Piri's own margins list ~20 sources: 8 Ptolemaic, 4 Portuguese, one Columbus

the map arrives with its bibliography attached

REPORTED

Azimuthal equidistant: distance and bearing from the centre exact by construction

everything else must distort; the bench computes it live

MEASURED

Hapgood 1966: a projection centred on Egypt; sources older than the ice

Maps of the Ancient Sea Kings · carried by Fingerprints of the Gods

REPORTED

Ohlmeyer letter, 1960: the lower coast "agrees very remarkably" with the subglacial profile

an eyeball comparison against a handful of sounding lines

REPORTED

The map joins its southern land to South America; the real gap is ≈800-1,000 km

no Drake Passage anywhere on the skin

MEASURED

East Antarctic sheet ~34 Myr old; EPICA core continuous through ~800,000 yr

the one clock in this file no reading has ever moved

MEASURED

The redrawn chart and every digitised coast on this bench are traces

the ↻ jitter button shows how much the tracing matters

MODELLED

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The reading

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The projection · centre

Centre latitude30.0°N

Centre longitude31.2°E

Whatever centre you choose, distance and bearing from it are exact, and everything else pays for it. That trade is the whole projection.

Graticulethe real Earth's grid, projected

Distance ringsevery 2,500 km, true by construction

The fragment's windowwhat the surviving skin covers

Portolan skeletonthe geometry the chart actually wears

The trial · southern land view

Subglacial Queen Maud coastthe claim's candidate · MODELLED trace

Modern ice coastthe control nobody's theory predicts

Patagonia, bent eastthe sceptics' candidate

The Drake Passage cardthe strait the map does not have

The map coast in the fits is a hand trace of a 500-year-old drawing. Jitter redraws it within an honest tolerance and reruns every fit: conclusions that move with it are about the tracing, not the coasts.

Display

Labels

Parchment finish

Readout · live

Projection centre

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Cursor from centre

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Fit · subglacial

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Fit · ice coast

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Fit · Patagonia

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Drake Passage

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Digitisation

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What is measured vs modelled here

Measured: the azimuthal equidistant mathematics, the least-squares similarity fits and their RMS numbers, the Drake Passage distance, the modern coastlines (Natural Earth 110m), the ice-sheet and ice-core ages. Reported: the fragment's date, signature and rediscovery; Piri's marginal source list and the notes on the southern land; Mallery's broadcast, the Ohlmeyer letter, Hapgood's projection claim, and both published verdicts. Modelled: the redrawn chart layout, the digitised map coast, the subglacial trace, and the fragment-window box. Reading: whether the southern coast is Antarctica, convention, or a bent Patagonia. Both cards hang in the file view, equal size.

The fitting model

The map's southern coast and each candidate are resampled to 48 points by arc length; a least-squares similarity transform (scale, rotation, translation, no reflection, both coast directions tried) maps the trace onto the candidate; RMS is reported in the candidate's own kilometres and as a share of its coast length. The subglacial candidate is a schematic trace of published outlines and is tagged accordingly; the other two come from the same public dataset as the world map. A fit this free is generous by design: if a claim cannot win even here, it cannot win.

Where this drawing takes liberties

The chart view is a redrawing of the fragment, not a facsimile: the well-sourced coasts (Iberia, West Africa, Brazil) follow real Natural Earth outlines bent into the parchment's layout, because the original's Portuguese-sourced coasts genuinely are that good; the Caribbean and the southern land keep the map's own period drawings, because those distortions are the story; notes, roses and creatures sit where the originals sit. The 1949-52 seismic data behind the famous letter were a handful of sounding lines, and no bench can redraw what was never surveyed; the subglacial trace stands in for the published outlines and says so. The projection mathematics, the fit numbers, the Drake distance and the ice chronology take no liberties.

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