Blog: https://bertt.wordpress.com/2025/01/10/creating-interactive-3d-hiking-map/
Live demo: https://bertt.github.io/ordesa_gr11/
2025-11-04: Fix terrain viewing PMTiles in FireFox by renaming .pmtiles to .pmtiles.gz
protomaps/PMTiles#584 (comment)
2025-01-10: Original coding