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Ngā Tohuwhenua Mai Te Rangi: A New Zealand Archeology in Aerial Photographs

The development of aerial photography

The development of aerial photography

Aerial photography can be used for four broad purposes in archaeology: as illustration, for research as data in its own right (where the virtues of illustration are applied to create new knowledge), as an aid to field research and excavation, and finally as an aid in determining the rate of destruction of sites and measures needed to conserve them. 5

After being used in the First World War for reconnaissance in both the Near East and the European theatres, 6 aerial photography was quickly grasped by the United Kingdom Ordnance Survey as an essential too for archaeological survey and mapping. In 1924, concluding a paper on 'Air Survey and Archaeology', O.G.S Crawford noted:

It is difficult to express in suitable words my sense of the importance of air-photographs for archaeological study They provide a new instrument of research comparable only to that provided by excavation. . . . They are not a substitute for fieldwork, but they are the most powerfually of the field archaeologist. . . . As a revealer of almost vanished earthworks they are superior in every way to observation on the ground. . . . and it is to be hoped tha they will figure largely in illustration of future books which may be written about the earthworks of a country . . . 7

In a subsequent paper, 8 Crawford and Alexander Keiller reviewed the history of aerial photography, and first systematically described the distinction between page 17 archaeological sites indicated only by changes in crop patterns (stunting or abundance of growth known as 'crop marks') caused by archaeological features beneath the surface, and sites which could be recognised from their surface relief alone 9 —techniques to which we shall return shortly. Indeed from about this time, once the pioneering work of recording the surface relief of earthworks or monuments such as Stonehenge or Bronze and Iron Age fortifications had been completed, attention turned much more to crop marks. Over the years since, Cambridge University has collected aerial photographs which have been used for many publications on the historical landscapes and sites of the United Kingdom. 10

In New Zealand in this same era, an interest in recording and making sense of the mark of human beings in the landscape is apparent in the early work of W.H. Skinner and S. Percy Smith, 11 both surveyors by profession, and in the writings of the ethnologist, Elsdon Best. 12 All were great interpreters, and not just for a European audience, of the Māori traditions of that same landscape. 13 Elsdon Best was publishing on pā at the same time as O.G.S. Crawford in England was publishing aerial photographs of Iron and Bronze Age hill-forts, but there is not the slightest hint in Best's writings that aerial photography might have been of use, nor any apparent interest in the potential of aerial photography for historic site work.

By the late 1930s aerial photography was being widely used in New Zealand, 14 and by 1945 there was full coverage for military purposes of the coastal districts. In New Zealand, a comprehensive archive of aerial photographs was built up. 15 Aerial photography from the time of the Second World War is still filed and available from the Department of Survey and Land Information.

However, it was not until 1947 that a paper on New Zealand archaeology and air photography, covering sites such as Papamoa (Bay of Plenty), the Wairau 'canals', and pā at Pakipaki, central Hawke's Bay, was published by G. Blake-Palmer, a general practitioner and later public servant. 16 His paper usefully reviewed the English experience and discussed matters of scale, the then-existing corpus of vertical aerial photography, crop marks and optimum seasonal and diurnal lighting conditions. Shortly after, Leslie Kelly published a booklet on Marion du Fresne, the French explorer, which used aerial photographs to illustrate the historical landscapes of the Bay of Islands. 17 Overall, however, Blake-Palmer's paper does not appear to have been particularly influential. The Wellington Archaeological Society did have lectures by him, and the use of aerial photographs was common in the extensive surveys of the Wellington region conducted by the society in the early 1960s, and surveys elsewhere in the lower North Island, for example, Colin Smart's work in Whanganui. 18

Blake-Palmer's paper was, of course, before its time, since there were no full-time practising field archaeologists in New Zealand until a decade later. In 1957 Jack Golson discussed the use of aerial photography, 19 but it was not until the publication of Archaeology in North Taranaki by Alastair Buist in 1964, 20 one of the more distinguished reports produced from that 'boom' decade in New Zealand amateur archaeology, that the potential of aerial photography for illustration and analysis began to be fully realised. Here for the first time, in a modestly produced book, were extraordinary images of the Taranaki historic landscape, emerging through the limitations of the printing. Subsequent books which have used aerial photographs for illustration have been J.D.H. Buchanan and David Simmons's Māori History and Place Names of Hawke's Bay, a superb historical landscape illustrated by black and white photographs by New Zealand Aerial Mapping, Ltd; 21 Barry Brailsford's The Tattooed Land, a study of pā in the South Island; 22 and some recent books on Taranaki and the Waikato, notably work by Nigel Prickett and F.L. Phillips's Ngā Tohu a Tainui 23

These books use aerial photographs by way of illustration for a text which is more concerned with traditional and archaeological knowledge. With the exception of the Buist monograph, they are not strong attempts to use aerial photographs as a source of new knowledge. There have been attempts (unpublished) to map individual sites using aerial photography, notable examples are: Te Pōrere (discussed in chapter 9); a pre-European pā at Hawai in the eastern Bay of Plenty; Ruapekapeka (discussed in chapter 7); some of the Auckland volcanic cones; Pouēua in the Bay of Islands; and Tapui near Manūtūke, Gisborne. 24 With the exception of the last two, all these exercises have produced results of indifferent archaeological value, mainly because they were done by technical photogrammetrists and not closely enough interpreted to yield informative archaeological results— for example, walls or banks constructed by human beings were not distinguished from naturally occurring high points or features. Aerial photographs are also used quite widely in the field to assist archaeological mapping and page 18site location, and these results are filed as site records with the New Zealand Archaeological Association. Such site records are a source of new knowledge, although they have seldom been gathered into a published work.

Hawke's Bay seems to have led the development and use of aerial photography in archaeology, because the principal company involved with aerial photography, New Zealand Aerial Mapping, Ltd, is based there, and because sites in the region are generally well sculpted into the ground and maintained in grass—ideal candidates for aerial photography. Les Groube, formerly a lecturer in archaeology at Auckland and Otago universities, was influential in the 1960s in guiding his students in the use of aerial photography. He also carried out aerial photography in Hawke's Bay in the early 1960s. 25 Another of his important projects was the mapping of site locations in the Bay of Islands for a pioneering study of site distribution. 26 Elsewhere, not far from the Hawke's Bay region, the Royal New Zealand Air Force photographed the Waiu pā complex, situated at an altitude of 1,100 m on the southern edge of the North Island's volcanic plateau. Te Pōrere (to be discussed in chapter 9) was also photographed from a helicopter at about this time by the late Ormond Wilson, to record its restoration. In the South Island, Hardwicke Knight also photographed a number of sites in the early 1960s (his photographs are in chapter 5).

The most successful attempt to date to generate new knowledge from stereoscopic aerial photographs is that of Foss and Helen Leach of the University of Otago, whose work was influenced by Les Groube. Helen Leach's published maps of garden plots and stone rows or walls in Palliser Bay 27 were significant both in detail and in the extent of features covered. Many purpose-flown vertical aerial photographs at a large scale (approximately 1:1,600) were used to map the coastal strip, with most of the detail checked in the field. (At this scale, a wall 2 m wide on the ground is 1.25 mm wide on the photograph.) In the course of the work she encountered and solved problems arising from lighting (high overhead or strongly oblique) and its effect on her ability to map the walls; changes in specific forms of vegetation cover on the walls, allowing them to be recognised; the loss of data due to blanketing vegetation cover; and distortion of the image at the edge of the lens. Most importantly, Helen Leach noted the value of the aerial view in being able to detect pattern and functions in features that defeated clear interpretation in the ground view. 28

There have also been important regional surveys using low-level oblique aerial photography, such as Nigel Prickett's work in Taranaki, already mentioned. Another source used in this book was a survey of the Waikato undertaken by Kees Sprenger and Steve Edson of the Waikato Museum of Art and History in 1980. Little published, Sprenger and Edson's is the finest low-level aerial photographic survey in New Zealand, covering a landscape of great historical interest.

In the early 1980s Auckland University's Audio-Visual Unit also began to use oblique aerial photographs on sites. In 1982 Reg Nichol, then a student at Auckland University, with Godfrey Boehnke taking the photographs 'hung on a strap out of the door of a high-winged light aircraft', carried out a low-level survey of Hamlin's Hill, just south of the Auckland urban area. Nichol had thought that a regular pattern of parallel lines showing on the surface of the hill, and which had long puzzled the student excavators, were pre-European cultivations. 29 The wider picture of the hill, unavailable in the ground view, convinced him that the lines resulted from European ploughing. In 1986 also using the university's audio-visual unit, Doug Sutton, a lecturer, arranged comprehensive low-level vertical and oblique aerial photography of Pouērua, a heavily settled volcanic cone in the inland Bay of Islands.