Review: Maps for Time Travelers

G.T. Dempsey


Mark D.McCoy Maps for Time Travelers: How Archaeologists Use Technology to Bring Us Closer to the Past (University of California Press, 2020), pp. xviii, 257  ISBN: 9780520303164  $26.95 Amazon | Bookshop

    This book’s provocative title is, indeed, accurate but only half so.  As advertised, it is a cogent survey of the geospatial technological advances over the last few decades which have enabled today’s archaeologists to map — that is, create digital versions of — the ancient world.  But it is also an engaging introduction, for the general reader, to the very nature of archaeological research:  ‘We are the only creatures on the planet, as far as we know, who can imagine what the world was like before we were born.’

     The author is a professor of anthropology whose area of expertise is the archaeology of the Pacific islands in the era before contact with the outside world.  From his own professional experience, he is particularly concerned that his readers be aware that ‘most of the human past [occurred] before writing was invented.’   His first two chapters (Part I) are a consideration of man’s historical curiosity and of the nature of what this ‘speculating about the past’ by us has produced:  from Neolithic cave paintings to Mark Twain’s A Connecticut Yankee in King Arthur’s Court to the earliest scientific archaeological explorations of this unwritten past by such as V. Gordon Childe’s studies of Stone Age Europe.  In these chapters, at times it seems we learn perhaps even more about time travelling, science fiction style (especially Dr Who), than we do about actual archaeology.  The discovery of carbon-14 dating, following on World War II, literally unshackled archaeologists working in periods before written documents.  Before that, working out how old a site — a deposit or a ruin — might be depended on such luck as finding pottery which could be sequentially dated (and even that only gave the archaeologist a relative dating).  ‘Radiocarbon gave us a tool to create chronologies using almost any biological material that we might find.’   Dating combined with location enabled the archaeologist to meaningfully interpret evidence of ancient lives.  But, the author cautions, ‘recording the location of things is just the first step.’  It was Global Positioning System (GPS), a product of the Cold War and for a long period a closely guarded military secret, which keyed the advance of archaeological mapping beyond the ‘site’ to knowledge of ancient cultures.  

     The three chapters of Part II give us the story of the development of mapping technologies over the previous century.  First came aerial mapping as man took to the skies.  Air photos revealed patterns of human use of the landscape invisible on the ground.  Grass grows differently where a ditch once stood.  Crop marks.  The route of Roman armies can be traced by such evidence of their encampments.  A phenomenon I experienced personally one extended summer in Ireland when an abnormally prolonged drought so dried out the grass in the backyard of my house that the outline of a long-filled in swimming pool emerged.  Satellite photography followed, increasingly sophisticated and precise.  Radar mapping from outer space.  In 1981, such imaging produced what looked like rivers in the Sahara.  Follow-up investigations, ‘ground truthing,’ produced physical evidence of major rivers that had not flowed for thousands of years.  Aerial laser scanning — ‘airborne lidar’ — has penetrated jungles to map Mayan cities and has traced out from the sea-bed an atlas of Doggerland, the peninsula which jutted out from Europe into the North Atlantic in Mesolitic times before the British Isles separated from one another and from the mainland.  Geographic Information Systems (GIS), the digital mapping software, was our author’s own geospatial technology starting-point, back in the 1990s.  Antique maps are often works of art but their makers tended to be ‘too good at mapping what they wanted to see.’  Still, their maps are historical documents; and, as such, they are being digitalised. The use of GIS in archaeology is intricate; chapter 6 provides a most useful introduction and guide to this specialized subject.

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     The three chapters of Part III move from method to subject — each chapter addresses a discrete subject:  travel and migration, food and farms, reverse engineering.  ‘One of the ripple effects of advances in geospatial technologies is that we have rich, high-precision data on the movements of just about every kind of creature on our planet.’  This has proven particularly fruitful in the reconsideration, by paleoanthropologists, of the peopling of the Americas.  While the Arctic land-bridge scenario has not been discarded, there is ‘a growing consensus that paleo-coasts were the route taken by the first people to colonize the Americas from Asia.’  Our author’s expertise in the colonization but a millennium ago of the islands of New Zealand in the far South Pacific — ‘the last major movement to permanently occupy a substantial land-mass previously unoccupied by people’ — undergirds the thesis.  Similarly, the ‘meta-analysis of fish bones in the Pacific Northwest is…a good example of how geospatial technologies can [provide us with] an idea of what kinds of strategies [people were pursuing] to feed themselves.’   Finally, ‘reverse engineering’ is employed to try to figure out how ancient societies worked from — for example — the lay-out of their cities, weighing the significance of the siting of commercial structures such as markets against that of palaces and other ruling structures.

     The final chapter returns to the concept of archaeology as time machine.  The concluding message?  ‘Archaeology is as close as we are going to get to visiting the past.’  This book is sparingly but usefully illustrated.  I was particularly taken by the photograph of three-million-year-old footprints (preserved in solidified volcanic ash in Tanzania). 

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About the author
G.T. Dempsey
G.T. Dempsey is a Research Associate in the history of Late Antiquity at the University of California at Davis and, as a retired American career diplomat, he is also a commentator on American foreign policy.