Over the last few years a new tool has been applied to the problem of measuring topographic change of the Elwha watershed and floodplain. LiDAR (Light Detection and Ranging) uses a focused light source to develop precise measurements of range to an object. With its extraordinary high sampling rate it can be used to develop comprehensive digital terrain models at very high resolutions. Repeat surveys can efficiently identify topographic changes. Amy Draut and Josh Logan of the USGS recently put together this LiDAR derived view of the lower Elwha River and floodplain, which is pretty cool:
I am part of a team that was recently funded to start collecting LiDAR derived data on the morphology of coastal bluffs on the Strait of Juan de Fuca. Once we get a few repeat surveys we are going to be able to start calculating erosion rates that are going to be far better than anything we've developed before...
looking forward to it...
Light-eyed?
8 hours ago
2 comments:
Pretty awesome. I think I see the survey stations in there - circular areas of high point density. The shadowing effects in the data are beautiful...
I'm curious about the effort and cost to use a system like this. I've been doing some topo surveys in a remote area of Alaska looking at a possible active fault, and conventionally flown LIDAR has been outside my price range. Last summer I surveyed about 1000 points by hand using a mapping grade Trimble GPS, and that data has been valuable, but rather sparse.
Didn't Clallam County do a LIDAR survey five years or so back? It used to be online, but they may have dropped access for budget reasons.
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