. . . . "2026-06-27"^^ . . "Sentinel-2 equal-area HEALPix power-spectrum outcome" . "The angular power spectrum of a Sentinel-2 scene can be computed end to end on an equal-area HEALPix grid on the WGS84 ellipsoid with the GRID4EARTH stack\n(healpix-geo + healpix-analyse). Because every HEALPix cell covers the same surface area, the resulting spectrum carries none of the latitude-dependent area\nweighting that a lon/lat grid would impose — supporting the claim by construction. The spectrum shows the expected monotonic power-law fall-off with\nspatial frequency, the signature of a natural surface-reflectance field." . . "Configuration and result recorded in results/powerspectrum.json:\n- scene S2A_22WEV_20190723, band B04 (red, 10 m), 256×256 px window (~2.6 km)\n- equal-area HEALPix at depth 18 (nside = 262144), ellipsoid = WGS84\n- field sampled at equal-area cell centres, then radially-averaged isotropic power spectrum computed with healpix-analyse `ps`\n- the spectrum (results/powerspectrum.png) falls off monotonically with spatial frequency on a log–log axis (power-law behaviour), with no latitude-dependent amplitude term, because the cells are equal-area by construction.\n\nGithub repository: https://github.com/annefou/healpix-analyse-s2-powerspectrum" . "The repo demonstrates the equal-area pipeline rather than quantifying the lon/lat bias it avoids: no side-by-side lon/lat baseline spectrum is computed here, so\nthe bias magnitude is argued by construction, not measured. Single scene, single band, single date; no atmospheric, cloud, or coastal effects; generalisation to other sensors and to a controlled multi-latitude comparison is left to follow-up." . . . . . "Anne Fouilloux" . "2026-06-28T15:46:05.059Z"^^ . . . . . "Sentinel-2 equal-area HEALPix power-spectrum outcome" . . "RSA" . "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" . "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" . . .