Uses Proj4js 2.22.0 MIT runtime for actual Mercator, Lambert azimuthal equal-area and orthographic coordinate transforms. Current repository commit and pinned runtime release recorded in research. Survey cells are synthetic geographic rectangles; graticule only, no political boundaries. Projected cell area uses corner quadrilaterals, so finite-cell ratio is approximate.
Repository https://github.com/proj4js/proj4js
Commit 7b94f6be407e25ea4b8b5ae80f0fece279a79ea4
Complete editable adaptation: all local HTML/CSS/JS files. No build required.

Source lineage: original interactive mission design around translated computation; upstream project is a maintained browser-native projection library. Targeted browser-source searches found no qualifying maintained licensed app for this exact experiment; this port uses only the disclosed algorithms. Current relevant inspiration and research are preserved in worker evidence.