Aerial and Spaceborne Remote Sensing in African Archaeology: A Review of Current Research and Potential Future Avenues

Abstract

Africa represents a vast region where remote sensing technologies have been largely uneven in their archaeological applications. With impending climate-related risks such as increased coastal erosion and rising sea levels, coupled with rapid urban development, gaps in our knowledge of the human history of this continent are in jeopardy of becoming permanent. Spaceborne and aerial remote sensing instruments are powerful tools for producing relatively complete records of archaeological settlement patterns and human behavior at landscape scales. These sensors allow for massive amounts of information to be recorded and analyzed in short spans of time and offer an effective means to increase survey areas and the discovery of new cultural deposits. In this paper, we review various case studies throughout Africa dealing with aerial and satellite remote sensing applications to landscape archaeology in order to highlight recent developments and highlight future research avenues. In particular, we argue that (semi)automated remote sensing methods stemming from machine learning developments will prove vital to expanding our knowledgebase of Africa's archaeological record. This is especially important for coastal and island regions of the continent where climate change threatens the survival of much of the archaeological record.

Geographic Disparity in Machine Intelligence Approaches for Archaeological Remote Sensing Research

“…Mongolia also emerged as a top country in the publication of neural network literature linked to archaeology. One potential reason for this imbalance stems from funding opportunities [43,72]. When analyzing published archaeological MI literature in Web of Science, most studies were conducted by affiliates of France's Centre National de la Recherche Scientifique (CNRS), Italy's Consiglio Nazionale delle Ricerche (CNR), the Chinese Academy of Sciences, and the University of California system in the United States (Figure 4).…”

“…In the developing world, where funding is limited compared to places like Europe, foreign scholars with monetary support tend to be responsible for the development of MI methods (when they exist) [43]. A survey conducted by ref [72] found that most R&D expenditures in Africa are covered by international grants outside of the African continent.…”

“…Specifically, these methods are highly utilized by researchers in the Global North (e.g., United States and parts of Western Europe), but other regions produce very few studies, in comparison, dealing with archaeological MI applications for remote sensing (Figure 2). Elsewhere, my colleagues and I have discussed this issue, illustrating that important developments in automated archaeological procedures have been underrepresented in archaeological literature from developing countries, particularly those in the Southern hemisphere [6,43]. However, robust quantitative evaluation of the problem within archaeology has not yet been undertaken.…”

Detecting Change at Archaeological Sites in North Africa Using Open-Source Satellite Imagery

“…PlanetScope imagery offers exciting possibilities for regular monitoring of sites, but has not yet attracted significant attention in the archaeological remote sensing literature; few projects have adopted it. For example, Davis and Douglass' recent review [7] neglects to mention it. It is not completely open-source, however a free license for a limited quantity of data per month is available for many types of stakeholder.…”

“…In this paper, we demonstrate the results of applying a bespoke change detection workflow using Google Earth Engine to two case studies ( Figure 1); the Aswan and Kom-Ombo area in Egypt (collaborating with the Aswan-Kom Ombo Archaeological Project, AKAP, directed by Maria Gatto and Given that it allows rapid recording via a bird's eye perspective, remote sensing has been an important part of archaeology in North Africa for several decades, although modern high-resolution imagery is underutilised [6]. Davis and Douglass' recent review paper [7] (p. 11 Figure 1) describes this trajectory in detail and maps the geographical range of these studies. Tapete and Cigna's review shows the recent expansion of scientific literature discussing satellite imagery for looting detection [8].…”