Alva Review-Courier -

ENFIELD, N.H. (AP) — Scanning an empty field that once housed a Shaker village in New Hampshire, Jesse Casana had come in search of the foundations of stone buildings, long-forgotten roadways and other remnants of this community dating to the 1790s.

But instead of a trowel and shovel, Casana and his Dartmouth College colleague Chad Hill are using a drone equipped with a thermal imaging camera and mapping instruments. The camera can identify remnants of buildings and other structures up to several feet below the surface, since the temperatures of that brick or stone material is often warmer tha...