AZGS is deploying drones to assess geologic features. To do so, and to register imagery precisely, we use a series of markers to assist during post-processing. In this case, Brian Gootee and Joe Cook have positioned markers along the shores of Lake Mead in northwestern Arizona as part of a study of the Mead Slope fault.
Beard & others, 2007, Preliminary Geologic Map of the Lake Mead 30' X 60' Quadrangle, Clark County, Nevada, and Mohave County, Arizona. https://pubs.usgs.gov/of/2007/1010/