Aerial Archaeology in Ireland - The Heritage Council

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3.2 Aerial Platforms
The equipment required to capture these various forms of aerial imagery can be mounted on a range of different aerial ‘platforms’.
While aircraft are most commonly used, satellites orbiting the Earth at a much higher level are also becoming more important.
Various means of raising equipment above the ground at much lower levels can also be used for specific applications where fine
detail is needed.
Helicopters and Fixed-wing Aircraft
There appears to be divergent opinion in Ireland on the relative merits of using helicopters or fixed-wing aircraft for oblique
photography. In terms of cost, hiring helicopters is significantly higher, though some claim that this is partly offset by the
ability to manoeuvre swiftly into the best position to obtain ideal lighting conditions, rather than having to circle extensively.
For the purposes of taking high-quality photographs for publication and other uses in illustration and publicity, Con Brogan
of the NMS uses helicopters. Some practitioners argue that the advantages of helicopters in terms of manoeuverability,
accuracy of positioning and low-level operation make them so superior to fixed-wing aircraft that they would not consider
using a fixed-wing platform. But for others, fixed-wing aircraft offer the considerable advantages of cost and range. These are
crucial considerations, particularly for general reconnaissance. The close collaboration and mutual understanding between the
photographer and the pilot of a fixed-wing aircraft — which Raftery (1944) highlighted in the first years of aerial archaeology
in Ireland — can also go some way in offsetting the advantages of helicopters in terms of positioning.
There is no single right answer to the question of helicopters versus fixed-wing aircraft. It is not only a matter of cost, as it also
involves individual experience and the purpose for which the photography is being undertaken. It is ultimately the quality of
the imagery that counts. As a ‘user’ of the results of aerial survey in the context of advising the National Roads Authority on
archaeological issues, Ronan Swan (pers. comm.) observed that taken as a whole, there are no obvious differences in quality
attributable to the use of helicopters or fixed-wing aircraft. Quality issues more often tend to concern photographic skills,
and the quality of descriptive identification, interpretation and pinpointing of site localities in ways that are useful for further
stages of work.
Figure 19: Two stone-built enclosures at Carrig Aille, Co. Limerick, part of the Lough Gur complex. From this high-quality, low-level aerial imagery, the
form of the monuments and their prominent position on a rock promontory are clear. It is also possible to see that the monuments are in generally
good, stable condition in appropriate land use, with no serious problems of rutting, poaching, erosion or scrub encroachment (Department of the
Environment, Heritage and Local Government)