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Comparing Lidar data to old survey maps changed how I see my local digs
I spent years digging test pits around my county here in Vermont, just guessing where old foundations might be. Then a buddy showed me a Lidar scan of a site I knew well, a 1700s farmstead I had mapped with a total station over two summers. The Lidar picked up subtle ground depressions that my flat survey map totally missed, like a root cellar and a second barn foundation. Layering the two together, the Lidar revealed the landscape memory way better than my tapes and compass ever could. Now I start projects by pulling Lidar from the state's open data portal, and I only use ground survey to check specific spots. Has anyone else mashed up these data sets on a site and had old features pop out that you never noticed before?
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schmidt.amy1mo ago
That bit about the "landscape memory" is exactly right. I had a similar thing happen with a 19th century mill site in Massachusetts. The old maps showed one building, but the Lidar revealed a whole series of drainage ditches that led to a collapsed overshot wheel pit, something that was completely invisible on the ground even after leaf-off. My advice is to always check the Lidar in the winter when the vegetation is down, you get way better return signals off the bare ground. Have you tried adjusting the hillshade angle to bring out different features?
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