Geolocating a random island using geometry and CUDA programming

	Geolocating a random island using geometry and CUDA programming(yassa9.github.io)
	517 points by yassa9 2 days ago \| 86 comments
	tl;dr: To geolocate a resort island from a single photo, the author extracted a geometric fingerprint (triangle of three landmasses with angles and distance ratios) and brute-force searched OpenStreetMap's global coastline dataset, using CUDA to test 80.7M candidate triples in 204ms on an RTX 3050. Successive filters—open-water rectangle test, coral cay shape/compactness, Sentinel-2 NDVI vegetation check, and Copernicus DEM elevation—narrowed 141K polygons down to 26 candidates, ultimately identifying Oan Resort in Micronesia (7.36°N, 151.76°E) with the camera facing NW.
	HN Discussion: ↑Praise for the writeup's quality, clarity, and human-authored style •Connects the technique to established terrain contour matching used in missiles and drones •Notes similar approaches used by JPL for Mars landing localization ↑Highlights OpenStreetMap's value for OSINT and geolocation work ~Suggests additional shortcuts like sun position or visual geoguessing could simplify the problem