GOLDONGO is a terrain-screening tool. It scores every stream segment in Peru for the physical conditions that let heavy minerals settle, and ranks them — so you can decide which streams are worth a visit before you leave the house.
A high score means a stream segment has the trap geometry to concentrate heavy minerals — not that there is gold upstream. Madre de Dios placers are rich and heavily worked; the Andean headwaters are steep, cold and remote. A region to read from a desk long before a boot touches it.
The score reads four shapes out of the elevation model. Each one is a place where the water slows and the heaviest grains drop first.
Where a steep reach flattens, the current loses the energy that carried heavy grains. Gold drops before anything else.
Water runs fastest on the outside of a bend and slowest on the inside. The bar on the inside is where the heavy fraction settles.
Where a tributary joins, the flow slows and spreads. The downstream side of the confluence keeps what both streams carried.
Where the valley narrows to rock, the bed is scoured to bedrock and every crack works as a riffle.
Each segment gets one score from those signals. Scores compare within a region — same elevation base, same rules — not across regions.
Planned: Copernicus GLO-30 (30 m); the Andean slopes are steep enough that 30 m already resolves the slope breaks.
The stream network is derived from the elevation model itself and cross-checked against OpenStreetMap waterways, HydroRIVERS and Sentinel-2 imagery, so the lines follow where water actually runs. Every source is open and credited in the footer.
Segments inside a protected area are forced to 0 and hatched red on the map. Official boundaries are incomplete in many countries — heritage sites rarely have a public service — so this gate can miss. Verify an area’s status yourself before you go.
Beta. The whole country is scored: 4.05 million stream segments from 30 m elevation data, Andes to Amazon. Lowland Amazon channels are the least reliable part. Free while in beta.
GOLDONGO is a terrain-screening tool. A score is not a promise of gold, and it is not a licence: check land status and follow local rules before you dig.