Cutline
A machine reading free satellite imagery of the Amazon, block by block, looking for one shape: a straight strip of bare ground cut into the forest since 2019 that appears on no map.
Live
What the machine is looking at right now (Sentinel-2, false colour: forest green, bare ground pink).
Blocks that contain a flag are never shown.
Log
Positions rounded to half a degree (~55 km).
How it reads the forest
Composite
Every clear Sentinel-2 pass of a 20 × 20 km block in the 2019 and 2026 dry seasons is cloud-masked and stacked into two clean images at 10 m.
Line filter
A matched filter sweeps 30 directions looking for a 1 to 4 pixel wide bright line with canopy on both sides, 400 m to 2.2 km long.
Reject roads
Water, curves, field edges and lines that carry on past their ends are thrown out. A strip has to stop.
Only new
The same line has to be forest in 2019. Old strips are already mapped; the frontier is what was cut since.
How good is it
Measured against 1,269 strips verified by The New York Times and The Intercept Brasil (2022).
Many of the misses are in open savanna or have grown back and are no longer visible at 10 m. Cutline only looks for strips cut into forest.
With the “forest in the before image” rule on, which only keeps strips cut since then. Every flag is still checked by eye against both dates before it counts.
On a known strip in Amazonas, the detector put its centre 40 m from the published coordinate.
Rules
No exact locations
Nothing finer than half a degree is ever published here. People living near these strips are the ones who pay when a location leaks.
A strip is not a crime
Villages use strips for medical flights, missions and supply. A flag means “new, unmapped, worth a look”, not trafficking.
Checked by a human
Nothing counts as confirmed until both dates are reviewed and the site is checked against official and open aerodrome registries.
Handed off privately
Confirmed strips go to journalists who already report on this, who can verify on the ground. Not to social media.