Air
Photo Interpretation for Archaeologists by D.R. WILSON
Tempus 2000. 256 pages, 123 b/w plates, 29
colour plates. ISBN 07524 1498 4 (£19.99)
This is an up-dated version of the Batsford 1982 publication
(Wilson 1982) of what has become known as the air photo interpreters’
bible. In fact the book contains absolutely essential information for
all archaeologists, be they students, professionals or interested amateurs.
So often archaeology is seen to be synonymous with excavation and the
text books focus on this activity; here is a source to redress the balance
and show the potential of information derived from the air.
The twentieth century saw the development, rise and
expansion of the subject of aerial survey, especially in obtaining photographs
– a data collection episode – which has not finished. This
book helps all of us to understand the impact of this work by focussing
on the interpretation of the information visible on aerial photographs.
The book was published at an appropriate time; the
expansion of aerial survey in Europe began with the end of the Cold
War and there have been many training schools, (in Hungary 1996, Poland
1998, Italy in 2000 and 2003). Having Wilson’s expertise and knowledge
so well illustrated has made the task of communicating the subject so
much easier.
Chapters 2, 3, 4 and 5 provide the basic guidance
for anyone wishing to develop their expertise in this subject. The inclusion
of a chapter on non-archaeological features is crucial; so much of what
is seen from the air is not of archaeological interest or even man-made
in origin. Filtering this information out from an archaeological point
of view is important but equally important is the understanding it provides
for the geological history of the country.
It is interesting to compare the differences between
the 1982 and the 2000 editions. The former is totally black and white,
with very sharp contrasts in the images; the fashion at the time. With
digital technology the images in the 2000 version are more subtle, with
less contrast. This may not seem as appealing initially, but on close
inspection there is more information visible than on the higher contrast
images. The colour section is a real bonus, even if the colour matching
is at times below its usual high standard (especially the false colour
infra-red image).
Other differences are the new sections on the developments
since 1982, not least the references to the National Mapping Programme
(an English Heritage project to map all the archaeological sites visible
on aerial photographs to improve our understanding of the historic environment).
The final section on Transcription and Data retrieval is new and even
in the short space of four years, there have been even more developments.
This is perhaps the weakest section of the book, as the purpose of air
photo interpretation is to communicate the information – and what
better medium than through a series of maps? However, to have dwelt
too long on mapping would have changed the emphasis of the book, and
this second edition has stuck to the original principles of explaining
the potential and pitfalls of air photo interpretation.
The geographical and chronological range of the book
is very good from the UK perspective, with the exception of the archaeology
of the twentieth century. This is a subject enjoying rapid growth which
aerial photography and interpretation is making some significant contributions
(see Cocroft & Thomas 2003). Even in the four years since its publication
another up-date would not be out of place in another year or two.
There is a small point of terminology and the use
of the term cropmarks. For simplicity’s sake I have preferred
the use of the terms cropmarks, parchmarks, and soilmarks to be one
word – as in earthworks. However Wilson uses the two word variant,
with a hyphen as in crop-mark. If my memory serves me correctly it was
David Wilson who explained his interpretation of the use of these terms;
crop mark as two words unless used adjectivally when it was hyphenated
as in ‘crop-mark photography’. Having followed this for
a number of years and edited so many reports for consistency I decided
that using these terms as one word was the most simple without losing
any accuracy. Sadly this text has the hyphenated version throughout.
The author suggests four purposes for aerial photography:
Illustration, Research, Excavation and fieldwork, and Conservation.
Although the order of these should not be significant the use of ‘Illustration’
as the primary role is worthy of debate. One’s view will depend
upon the type of job or the organisation you work for. My experience
suggests that it is research that is the most important aspect of aerial
survey, as it helps to develop Excavation and fieldwork projects as
well as providing invaluable information for Conservation. This is not
to denigrate, in any way, the use of aerial photographs for illustration
– a picture can speak a thousand words – but for the subject
to develop and grow its potential for research, as it is the most cost-effective
and productive means of discovering new sites and monitoring existing
sites, building and landscapes which form part of the historic environment.
A change which the author should have made was to
move the section on modern military features (page 193) to Chapter 3
(as he hints himself) but he takes the view that archaeologists see
these as ‘modern intrusions’; since 1982 I think this view
has changed dramatically. In the new edition figure 112 (in the chapter
on Non-archaeological features) still describes the 1939-1945 search-light
battery as if it is not archaeology.
Although the book does not list the address of Cambridge
University Committee of Aerial Photography (CUCAP), the organisation
which created most of the images in the book, it is worth noting that
CUCAP no longer exists but has been transformed into the Unit for Landscape
Modelling (ULM). This is now part of the Department of Geography and
maintains a flying capability, mainly for commercial surveys taking
vertical images but also engaged in some Research and Development, especially
in doing trials for Lidar (Holden, Horne & Bewley 2002). This technique,
which has come to archaeologists attention since 2000, may have as much
impact as aerial photographs did in the 1920s.
The good news is that aerial survey is still developing
and expanding; the contribution of this book is that it forms the solid
foundation for interpretation of remotely sensed images be they photographs,
satellite images or those derived from new remote sensing techniques
(Shell 2002).
Bob Bewley
English Heritage
References
Bewley, R. & Raczkowski, W., 2002. Aerial Archaeology. Developing
Future Practice. Nato Series 1: vol. 337, 173 –180
Cocroft, W.D., & Thomas, R.J.C. (ed. P.S. Barnwell), 2003. Cold
War: building for nuclear confrontation 1946-1989. Swindon: English
Heritage
Holden N., Horne, P., Bewley, R., 2002. High-Resolution Digital Airborne
Mapping and Archaeology. In Bewley, R. and Raczkowski, W. Aerial
Archaeology. Developing Future Practice. Nato Series 1: vol. 337,
173 –180
Shell C., 2002. Airborne High-Resolution Digital, Visible, Infra-Red
and Thermal Sensing for Archaeology. In Bewley, R. and Raczkowski, W.
Aerial Archaeology. Developing Future Practice. Nato Series
1: vol. 337, 181-195.
Wilson D.R. 1982. Air Photo Interpretation for Archaeologists.
Batsford.
Review Submitted: April 2004
The views expressed in this review are not
necessarily those of the Society or the Reviews Editor.
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