Martin J. F. Fowler

Abstract: The abilities of three satellite remote sensed image products (low spatial resolution LANDSAT Thematic Mapper (TM); medium resolution SPOT Panchromatic; high resolution KVR-1000) to detect archaeological features in the environs of the Iron Age hillfort at Figsbury Ring, Wiltshire, have been evaluated. Given prior knowledge of their locations, relatively large features together and those possessing a strong linear nature could be detected on the LANDSAT TM multispectral and SPOT Panchromatic image products. Near-infrared TM imagery showed promise for the detection of smaller features as a result of differences in vegetation cover, but was constrained by its low spatial resolution. High resolution Russian KVR-1000 imagery was found to be capable of detecting both upstanding and ploughed-out archaeological features without the need for prior knowledge of ground truth. It is concluded that satellite imagery, although not a substitute for conventional aerial photography, represents a complementary source of information when prospecting for archaeological features. In a regional context, low resolution multispectral imagery can be used for the prospection for areas of high archaeological potential through the use of image processing and modelling techniques and, together with medium resolution imagery can be used to prepare base maps of regions for which up to date mapping is not available. High-resolution imagery, together with conventional aerial photographs, can be used subsequently to detect and map archaeological features. Copyright © 2002 John Wiley & Sons, Ltd.

Abstract: Recently declassified intelligence satellite photographs acquired in the 1960s and early 1970s by the CORONA programme have been found to be an important source of low-cost, relatively high resolution, overhead photography that can be used in the prospection for archaeological features. Hitherto, the material has been used primarily to detect archaeological features in the arid regions of Asia Minor and the Middle East either in relief or through changes in soil tone resulting from the presence of former human habitation. In this paper the authors describe, for the first time, the detection of archaeological crop marks on CORONA KH-4B photography of southern England indicating that there could be a wider utility of the CORONA archive for archaeological prospection in temperate regions. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract: The capability of satellite QuickBird imagery for the identification of archaeological crop marks is herein presented and discussed for two test sites located in the South of Italy. The selected sites, dating back to Middle Ages, were buried under surfaces covered by herbaceous plants characterized by a different phenological status (dry/green) when the satellite data were acquired. The methodological approach adopted for the enhancement and extraction of crop marks is mainly based on the use of data fusion and edge detection algorithm. The main remarkable differences found for the two archaeological sites can be suitably linked to the different state of vegetation that caused a different spectral response. In particular, near infrared (NIR) spectral channel was able to better enhance crop marks observed for dry vegetation; whereas, Normalized Difference Vegetation Index (NDVI) was found to be more capable to better enhance crop marks observed for green vegetation.

Abstract: Spatial technology is integral to how archaeologists collect, store, analyze, and represent information in digital data sets. Recent advances have improved our ability to look for and identify archaeological remains and have increased the size and complexity of our data sets. In this review we outline trends in visualization, data management, archaeological prospecting, modeling, and spatial analysis, as well as key advances in hardware and software. Due to developments in education, information technology, and landscape archaeology, the implementation of spatial technology has begun to move beyond superficial applications and is no longer limited to environmental deterministic approaches. In the future, spatial technology will increasingly change archaeology in ways that will enable us to become better practitioners, scholars, and stewards.

Abstract: Multi-sensor airborne remote sensing has been applied to the Itanos area of eastern Crete to assess its potential for locating exposed and known buried archaeological remains, and to delineate subsurface remains beyond the current limits of ground geophysical data in order to permit future targeted geophysical surveys and archaeological excavations. A range of processing techniques (e.g., Reed–Xiaoli anomaly detection) have been applied to the CASI, ATM and lidar data in order to detect anomalies based on the premise that buried remains are likely to alter the physical and chemical characteristics of the soil compared with those of the surroundings due to variations in soil depth and drainage. Through a combination of CASI, ATM and lidar data, surface remains have been classified and mapped effectively using an object-oriented approach. The detection of subsurface remains is more problematic; however, the thermal data is most promising in this respect. The value of capturing multi- or hyperspectral data at a high spatial resolution has been demonstrated as well as the additional benefits of combining these with airborne lidar.

Abstract: Archaeological sites are sometimes visible in satellite images as soil or crop marks. At best, the marks are distinct, but they tend to have less contrast with the background than many other patterns in the images. Consequently, reliable automated detection based on pattern recognition is very difficult. Our method detects circle-shaped soil and crop marks in the panchromatic band of high-resolution satellite images of agricultural fields. Such circular marks may be caused by burial mounds. In our approach, local contrast enhancement is applied in order to make weak marks more distinct. The image is then convolved with ring templates of varying sizes, giving high absolute values at candidate circular mark locations. Each candidate mark is presented to an operator, who may reject it. We tested our method on Quickbird images from southeast Norway. The number of detected candidate marks could be varied by changing a threshold value. A reasonable compromise between not detecting too many false rings and at the same time detecting as many true rings as possible, might be when the number of false detections is approximately seven times the number of true detections. In this case, 11 out of 15, or 73%, of the strong rings were detected, and 5 out of 10, or 50%, of the fairly strong rings were detected. This is 16 out of 25 of the strong and fairly strong rings, or 64%. Archaeologists state that the software tool we developed will be helpful for locating potential cultural heritage sites. Although it makes many false detections, it will relieve the operators from time-consuming manual inspection of entire images. Copyright © 2008 John Wiley & Sons, Ltd.