About

Depth maps for the water you actually use

ShoalScope is published by Atlas Labs. It gives people who play on shallow water, kayakers, paddle-boarders, flats anglers, freedivers and small-boat skippers, a clear answer to one question: how deep is it here?

Method

How a map is made

1

We watch the water from space

Many clear-sky pictures of the same stretch of coast, taken over the last year, are stacked together so clouds, glare and boats disappear.

2

Colour becomes depth

Water absorbs light as it gets deeper, so shallow water looks different from deep water. A model trained on measured depths turns that colour into feet for every point of the map.

3

We check it, and show the score

A satellite laser measures the sea floor directly along narrow tracks. Those soundings are independent of the pictures, so comparing against them gives an honest accuracy for each map. The typical error is printed on every map.

What the numbers mean

  • Depths are below mean lower low water (MLLW), the same reference as US charts. Add the tide for the water you will actually have.
  • Accuracy is the typical error measured against the laser soundings, in metres by default (switch to feet with the m | ft toggle). Shallow, clear water is most accurate; murky water, seagrass and deep water are less so.
  • Updated is when the map was last recomputed, shown as "2 h ago" and as a full date when you hover.
  • Grey or blank areas are land, or water where no reliable depth could be estimated.

Coverage

We are rolling out maps along the US coast and the Caribbean, one shallow area at a time. The Spots page lists what is live, and the guides explain how to use each area. Each area is computed on a grid of 10 m or 20 m cells, shown here as a chip.

Contact

Atlas Labs · atlaslabsdaba@gmail.com. Suggestions for new areas are very welcome.

Credits

Basemap data © OpenStreetMap contributors via OpenFreeMap. Satellite basemap © Esri, Maxar, Earthstar Geographics and the GIS User Community. Place search by Nominatim.