Claim register
Claim Evaluation
Every claim is stated exactly, traced to its origin, and evaluated against the best supporting and the best opposing case. Scientific claims must expose their full reasoning chain — observation, measurement, calculation, prediction, physical test, result, replication — and declare per-model predictions BEFORE the result is shown. Appeals to authority (“science says”, “experts agree”, “the math proves it”, “settled”) are not evidence. Confidence is authored, not tallied. Preserve disagreement rather than force a conclusion.
Gleason's 1892 map is patented as a north-polar azimuthal-equidistant projection
SupportedUS Patent 497,917 describes Gleason's map construction as an azimuthal-equidistant projection centered at the north pole.
Origin: US Patent and Trademark Office, patent 497,917 (1893).
Best supporting case
The patent text itself describes the construction (equal linear scale of meridians from the pole). Modern d3-geo azimuthal-equidistant reproduces the same coastline geometry at matching scale.
Best opposing case
No credible opposing case on the patent's own text. Some interpret the map as a literal cosmological chart; that is a separate claim, not a patent-text claim.
Evidence
[supports] source statement Historical document — Patent 497,917 explicitly names the construction.
- ↳ US Patent 497,917 — Map of the World (Alexander Gleason) (Government)
[supports] source statement Historical document — Boston Public Library holds the master scan.
[supports] calculation Mathematical calculation — Rendering Natural Earth coastlines under d3-geo azimuthal-equidistant, centered at the north pole, matches Gleason's coastline placement.
- ↳ Natural Earth 1:110m Physical Coastline (Reference)
- ↳ d3-geo / d3-geo-projection projection implementations (Reference)
Circular-reasoning check
No circular-reasoning risks identified in the authored evidence chain.
Hidden assumptions
- The 1892 image and the 1893 patent describe the same construction (they do; the patent post-dates print).
Missing evidence
- Original printing plates would strengthen provenance; none currently traced.
Contradictions
— none recorded —
Reproducibility
- Directly reproducible: render coastlines in any d3-geo build with azimuthal-equidistant centered at 90°N.
Confidence · high
The claim is grammatically about the patent's own words plus a geometric reproduction. Both are directly checkable; nothing is inferred about the earth itself.
Confidence is authored, not tallied. It reflects primary vs. secondary evidence, source independence, methodology, conflicts, and reproducibility — not the count of sources.