by John F. Doershuk, University of Iowa Office of the State Archaeologist

OSA’s Director of Research Technology, Mary De La Garza, is into drones, technically known as “uncrewed aerial vehicles” or UAVs. Mary, a licensed FAA UAV pilot, now commands a fleet of three drones and two additional OSA staff members have, or will soon earn, their UAV pilot licenses. As OSA uses these drones in our university work as a statewide research center, we follow University of Iowa policy regarding UAVs and part of Mary’s duties is responsibility for OSA compliance in our drone work.

Using Drones in Archaeology

Mary is showing off her latest UAV, a Phantom 3. It’s very lightweight—well under three pounds even with the battery and camera—and highly maneuverable but Mary reports therefore also tricky to handle! The Phantom 3 has a built-in high resolution camera (HD, FHD, and UHD) and this unit can be swapped out for our GoPro Hero camera or FLIR thermal imaging camera. With the high resolution camera Mary can capture fantastic aerial videos of features at all sorts of scales of resolution. There are plenty of archaeological applications ready to be explored using this sort of fast-to-collect data. For example, a project area that has vegetation or wetland areas that make ground access and mapping challenging can often be readily viewed from the air. This can help cut costs as either a preliminary survey tool or to quickly capture images needed to fully document a historic property. Aerial views also sometimes reveal features that are obscured when viewed from ground-level. UAVs are also being used to inspect architectural resources such as bridges or difficult to access details positioned high on building facades.  Even in archaeology, UAVs can provide a way to examine site deposits in ways just not possible by the archaeologist on the ground such as this view of the Dixon site in western Iowa from above the Little Sioux River.

The FLIR thermal imaging camera has really interesting potential in archaeology. It has often been observed that vegetation grows differentially above or near different types of subterranean archaeological features such as stone walls, earth lodge depressions, historic foundations, and large middens. These growth differentials can sometimes be detected at ground level, but a drone perspective can really make these evident. Thermal imaging, reacting to temperature differences in soil and vegetation caused by differential moisture content, can be used to spot buried archaeological features even in the absence of surface differences noticeable to the human eye.

As tricky as flying the drones can be when weather conditions aren’t ideal, Mary reports her team’s expertise really comes to the fore in processing the data collected by these cameras. Using programs like Pix4D and AgiSoft to stitch imagery into 3D models and analyzing thermal band data to reveal archaeological features takes patience, experience, and skill! Mary is particularly interested in archaeological uses for her drones but is available to explore use for any sort of construction, compliance, or agricultural project. Contact Mary at mary-delagarza@uiowa.edu if you are interested in utilizing OSA UAV expertise!