DIGITISING HUMAN TRACKS: CHALLENGES AND DEVELOPMENTS

While rare in the geological record human tracks have in the last thirty years been found in increasing numbers, ranging from those of paleoanthropological significance like the tracks at Laetoli (3.66 Ma; Tanzania) and Ileret (1.5 Ma, Kenya), to those of interest to Holocene archaeologists. Human tracks provide inferences about stature body mass and gait, as well as data on hominin presence and behaviour (Bennett and Morse 2014; Human Footprints, Springer).

The study of human tracks, like other vertebrate tracks, has been revolutionised by the advent of digital data collection either via some form of optical laser scanning, or increasingly by the application of soft copy photogrammetry. Both now provide reliable means of creating high resolution digital elevation models of tracks in the field. The case for digital preservation in the conservation of soft-sediment and therefore highly erodible footprint sites has recently been made by the authors. With the availability of digital data there is now demand for sophisticated tools with which to visualise and analysis human tracks. The authors have pioneered the application of landmark based geometric morphometrics to the study of human tracks and have also recently developed a new ‘whole-foot’ approach that allows the registration of multiple tracks to produced measures of central tendency. This allows whole trackways or track populations to be compared statistically, increasing the analytical rigour available to the geoarchaeologist.

This paper provides an overview of these developments drawing on data from human footprint sites across the World. We focus on: the challenges of data collection in the field; compare optical laser scanning to photogrammetry; consider data storage and file formats; illustrate the development of bespoke freeware that allows tracks to be freely visualised by both scientists and public alike; and finally review the development of a new software suite for ‘whole-foot’ track analysis. Parallels with the analysis of other vertebrate track studies are made throughout.