CANYONFINDER

Frame an area on a map. Get the flow lines and every candidate vertical drop in it, from USGS 1 m lidar, in about a minute.

How it works

  1. Frame. Pan and pinch to the area and tap Use this view: Draw a box, or frame the area and use the view: up to 50 km² anywhere the 1 m coverage layer is lit. The tool asks the USGS whether a 1 m DEM exists there.
  2. Run. Tiles are fetched, the surface is hydrologically conditioned by breaching (never filling: filling erases the plunge pools that mark a drop), flow is routed, channels are extracted at a one-acre threshold, and every channel profile is scanned for steps at four scales (2, 5, 15 and 40 m). Flat terrain is skipped.
  3. Look and take. Drops on the map with their height in feet, filterable by size; tapclick one for its attributes. Export as shapefile or KMZ, or open the result directly in CalTopo and save it to your own map.

What a drop tells you

  • Step height, net of the channel's background gradient, in metres and feet.
  • Resolution limited: the fall is compressed into two metres or less of horizontal run, the limit of what a 1 m DEM can represent. Vertical or steeper. A strong positive signal.
  • Context truncated: the profile ran out of channel before the test could finish.
  • Edge truncated lines leave your box; their contributing area is understated.

Read before trusting

  • Every point is a candidate, produced by parameters that are still placeholders. Nothing here has been checked on the ground.
  • Lidar rarely reaches the floor of a tight slot. The USGS interpolation spans the gap with a smooth, fictional floor, exactly where the best drops are. Some real canyons will be invisible.
  • Designated wilderness constrains what is legal on the ground (no fixed anchors placed by mechanized means, no motorized access). The wilderness flag is not yet in this version.
  • Results are kept for 7 days at a link only you have. Anyone with the link can open them.