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What drains into this pixel?

Finding what drains into a point normally means walking the network: step upstream, follow every branch, keep going until the branches run out. The cost grows with the catchment. Here it is a lookup. Every land pixel stores two numbers, dfs_in and dfs_out — the positions at which a depth-first walk of the flow network enters and leaves that pixel. Pixel p is upstream of pixel q when dfs_in(q) ≤ dfs_in(p) ≤ dfs_out(q) — one integer comparison, the same at a headwater and at the mouth of the Amazon. Nothing is traced.

Global map(unavailable)Example basin (pixel-level)
Global map(unavailable)Not available in a browser: this answer exists at every one of the 22.26 billion land pixels, far more than a web map can draw. The pixel-level rasters are in the Zenodo archive. A browsable version arrives at reach level with FullRiver.
Example basin (pixel-level)Basin 8595: click a pixel and the upstream catchment comes back from one interval test
Base layer
What to draw

Interval query · basin 8595

Click anywhere in the basin. The click snaps to the nearest pixel with a large drainage area, marked with a star, so a click on a hillslope still returns a catchment.

The formula below follows whatever you pick above.

Site under development — pages may change daily. The current data release is archived on Zenodo. Comments on the dataset are welcome in the open discussion at ESSD; anything else, [email protected]