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13. A Comparative Guide to Applications
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13 A Comparative Guide to Applications JayK.Johnson In this concluding chapter, I would like to revisit a few of the central questions relating to the incorporation of remote sensing into the protocol for cultural resource management (CRM) archaeology in the United States. As was intended, most of these questions have been addressed in some detail in the preceding chapters. The first question is, of course, is there a place for remote sensing within the laws and regulations that guide CRM activities? Lockhart and Green (this volume) make it clear that while remote sensing is not explicitly mentioned, many of the CRM laws and standards set goals and guidelines that can best be satisfied using remote sensing techniques. In Great Britain, the change in regulations known as Planning Policy Guideline 16 that led to a florescence there in geophysical survey is only slightly more explicit, including the phrase “developers may wish to carry out geophysical surveys as part of their own initial archaeological assessment” (Gaffney and Gater 2003:22). According to Gaffney and Gater (2003:22), the more critical statement in the guideline is that “anything that is asked of the developer is ‘fair, reasonable and practicable.’” British developers have interpreted this statement in terms of cost effectiveness. This leads to the question of whether remote sensing site survey is more effective and less expensive than the more traditional techniques used by CRM-based archaeology in the United States. The simulation that Bryan Haley and I report in Chapter 3 makes a strong argument for the likelihood that better and less expensive data recovery would result from 306 ~ Jay K. Johnson the use of geophysical techniques on large, complex Mississippian sites. It is considerably more effective than shovel testing, a technique that has been adopted because there has been no other practical alternative at sites where ground visibility is limited. However, archaeologists have questioned shovel testing as a site discovery and evaluation technique in the United States for many years (Kintigh 1988; Krakker et al. 1983; Shott 1985, 1989). Kvamme (2003a:453) reaches similar conclusions about the advantages of geophysical survey over shovel testing. On Mississippian sites, remote sensing is likely to give a much better view of the structure and integrity of the site than controlled surface collections. And it is cheaper. It is also likely, given the level of response that we have gotten on these kinds of sites, that random or stratified random test pits and mechanical stripping of the plow zone could be dispensed with or radically reduced in scope and the fieldwork could move directly to block excavation. This would also save money and improve the quality of the data recovery. However, what about Woodland hamlets and Archaic camp sites? Would our simulation have worked as well on these classes of sites? At this stage in the development of remote sensing applications in North America, the answer would have to be no. When you download the gradiometer data from a Mississippian site and generate an image that includes a series of rectangular patterns, 3–4 m on a side, it doesn’t take much experience to conclude that the remains of burned, clay-plastered houses are preserved beneath the plow zone at that site. However, what if the structures at the site are much less substantial and the major intact cultural features are irregular pits dug into the subsoil ? These pits are also likely to be detected using the geophysical techniques we have described. However, their identification will not rest primarily on pattern recognition. In order to distinguish them from similar, noncultural features at the site, a fundamental shift will be required in the way that remotely sensed data are interpreted. As was emphasized in the introduction to the chapter on multiple instrument applications (Chapter 11), rather than relying on shape characteristics as has been the case in most archaeological geophysical research in the past, we must start doing “spectral” analyses of features. That is, we need to compare the way in which the feature is measured using as many instruments as possible. To give a simple example, the pit features relating to the Woodland component at the Walford site in western Mississippi show up in both the gradiometer image and the susceptibility image (Figure 13.1), as do the burned Mississippian period houses at the Parchman Place Mounds. However, the ratio of remanent magnetism to magnetic susceptibility, which can be approximated by dividing the gradiometer values...