The Zagora Infrared Photogrammetry Project
The primary goal of the Zagora Infrared Photogrammetry Project (ZIPP) was to record both the site of Zagora and the surrounding environment in two photographic wavelengths, regular light and infrared. It was hoped that this form of remote sensing would reveal unknown exposed and subsurface features in the area.
The science behind infrared photography is relatively simple. This excerpt comes from an my publication in the journal Archaeological Prospection.
“Thermography, more commonly referred to as Thermal Imaging, is the practice of translating infrared radiation into a pictorial representation of heat (Meola & Carlomagno, 2003). Every object that is hotter than absolute zero emits infrared radiation, with the amount of radiation released increasing with temperature (Gaussorgues, 1994). A thermal camera can assess the amount of infrared radiation being emitted and translate that into a thermogram, more commonly known as a thermal image. The principle of archaeological thermography is that as the sun rises and sets during the course of the diurnal cycle, subsurface remains will absorb and emit infrared radiation, with the amount of infrared transference dependent on variables such as moisture, material and density (Perisset & Tabbagh, 1981; Haley et al., 2002; Casana et al., 2014). If the emitted thermal radiation differs from that of soil surrounding the feature, it may be detected by a thermal camera (Kvamme, 2008a).”
The project ultimately ended up finding over 60 thermal anomalies and dozens of other features located both on the site and around the hinterland of Zagora. We discovered numerous unknown structures on the site and also helped confirm a number of the results discovered during geophysical survey carried out in 2012. These results are expected to be published within the next several months.
- Meola, C., & Carlomagno, G. M. (2003). Recent advances in the use of infrared thermography. Measurement Science and Technology, 15, R27–R58. https://doi.org/10.1088/0957‐0233/15/9/R01
- Gaussorgues, G. (1994). Infrared thermography. London, UK: Chapman&Hall.
- Perisset, M. C., & Tabbagh, A. (1981). Interpretation of thermal prospection on bare soils. Archaeometry, 23(2), 169–187. https://doi.org/10.1111/j.1475‐4754.1981.tb00304.x
- Haley, B. S., Johnson, J. K., & Stallings, R. (2002). The utility of low cost thermal sensors in archaeological research. Report Prepared for the Office of Naval Research NASA Grant NAG5–7671. University, MS: Center for Archaeological Research, University of Mississippi.
- Casana, J., Kantner, J., Wiewel, A., & Cothren, J. (2014). Archaeological aerial thermography: A case study at the Chaco‐era blue J community, New Mexico. Journal of Archaeological Science, 45, 207–219. https:// doi.org/10.1016/j.jas.2014.02.015
- Kvamme, K. L. (2008a). Remote sensing approaches to archaeological reasoning: Pattern recognition and physical principles. In A. P. Sullivan (Ed.), Archaeological concepts for the study of the cultural past (pp. 65–84). Salt Lake City, UT: University of Utah Press.