Detecting archaeological sites in the eastern Sahara using satellite remote sensing and digital image processing

Thesis

Advancements in remote sensing instrumentation are providing more detailed surveys of our planet using synoptic observations from a global, regional, and local perspective. This D.Phil. research project proposes novel techniques for detecting archaeological sites in the hyperarid desert regions and moisture-rich coastal areas of the eastern Sahara, by examining multispectral satellite imagery in the optical and microwave (radar) regions of the electromagnetic (EM) spectrum. The methodology uses sensors onboard spaceborne platforms (in contrast to airborne instruments or ground based geophysical survey) – weighted heavily towards an active radar approach. Landsat-7 ETM+, Shuttle Radar Topography Mission (SRTM), and PALSAR represent the principal imagery types used throughout this work.

Three case studies are presented, each setting out a comprehensive and well-documented protocol for archaeological site detection. The first uses Landsat ETM+ data to map and identify the distribution of ‘tell’ sites in the northwestern Nile Delta by applying a principal components transformation and a thresholding approach. The second case study produces a complete hydrologic map of the eastern Sahara from SRTM image (amplitude) and elevation data. Oases and ancient fluvial networks (palaeorivers) are mapped using the Normalized Difference Vegetation Index (NDVI) and from SRTM image data respectively. ASTER thermal infrared (TIR) is used to detect palaeolake deposits from their surface carbonate signatures. Additionally, topographic lake depressions and palaeoshoreline features are identified from SRTM DEM. The use of a DEM was found to provide a more favourable approach for mapping palaeolake systems compared to performing a spectral analysis. The final case study considers trading routes and their relationship to water sources. Imagery datasets produced over the course of the work are added to a Geographical Information System (GIS) in order to examine likely locations for new archaeological sites in Egypt’s Western Desert. Results from these investigations indicate that a fully multispectral strategy is preferred when isolating spectral signatures from archaeological materials.

Authors: Corrie, RK

• DOI: 10.5287/ora-jb9k8z4b1
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: satellite; hydrology; Egypt; archaeology; Remote sensing; GIS; radar; Sahara
• Subjects: Remote sensing