Satellite Remote Sensing for Archaeological Applications
Stewart, Christopher
Tor Vergata University, ITALY

Remote sensing techniques for archaeological analyses using satellite data from primarily ESA and Third Party Mission sensors are presented. The applied techniques take advantage of the different characteristics of the various sensors that can be exploited for the purpose of detecting archaeological features of interest concealed in a range of land cover types in Europe and North Africa. Features buried beneath the ground can affect the characteristics of the overlying soil, including its composition and ability to retain moisture. This in turn can alter the properties of vegetation that may grow on the surface. If the differences in the soil and vegetation over buried features compared to where there are no buried features are sufficient to render them visible to the human eye, they are termed soil and crop marks respectively. This study aims to identify soil and crop mark signatures in remotely sensed data that may be due to the presence of buried archaeological features. Results are presented of a number of cases where soil and crop marks are identified through the analysis of their spectral signature in optical multispectral and panchromatic imagery (Kompsat-2 and ALOS PRISM) and other cases where their identification is attempted through the analysis of their backscatter signature in polarimetric SAR imagery (ALOS PALSAR). [see example fig. 1.] Another method to identify buried structures is through the analysis of surface topography. Often features buried beneath the ground leave subtle traces of their forms which may only be visible by interpretation of data acquired through very high resolution topographic sensing techniques such as laser scanning and photogrammetry. The utility of high resolution DEMs created from ALOS PRISM stereo imagery to aid archaeological research by means of topographic analysis is assessed. An example is presented over Rome, demonstrating the utility of the technique to highlight topographic features of interest to the study of the archaeological record. [see example fig. 2.] Finally, techniques unique to SAR data are considered. The sensitivity of microwave backscatter to the roughness, density, composition and dielectric properties of materials render SAR an interesting tool for archaeological applications. Results of the use of C-band and L-band SAR (Envisat ASAR and ALOS PALSAR respectively) to identify buried structures in North Africa are presented. [see example fig. 3.]