Aerial Photography and Visualisation for Built Heritage - PhD Portfolio by Kieran Baxter
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Tuesday, 9 April 2013

Ye'll Tak' the High Road... Aerial Photography Altitude Comparisons at St Andrews Cathedral, Linlithgow Palace and Brougham Castle

I have recently had the opportunity to take some aerial photography from somewhat higher altitudes than I'm used to, allowing me to compare the process and outcomes of kite aerial photography with that of shooting in person from a light aircraft. Needless to say the two approaches are very different beasts, and the resulting imagery works in quite distinct ways. A convenient place to begin comparison is St Andrews Catherdral, which I tackled using both methods last month.

My first encounter was during a commission for Historic Scotland for a research project in collaboration with St Andrews University. The project will produce an experimental interactive interpretation panel, and the team were looking for some low level aerial perspectives of the current day site, upon which to overlay a reconstruction. The aim here was to gain enough height to separate the elements of the site without loosing the profile and context. Below is an outtake from the shoot looking along the remains of the - largely destroyed - main body of the cathedral. It is always an enjoyable challenge to photograph a lost structure and I think the large area of shadow in this picture helps to give a feel of the volume of the missing building.

St Andrews Cathedral, photograph taken from a kite aerial platform.
St Andrews Cathedral, photograph taken from a light aircraft.
Another feature of the top image is the proximity to the summit of the foreground "spire" (actually just the remains of one corner) which seems remote from the ground. Where the camera is in line with the tops of the structures the perspective is inverted, so that - while people and gravestones become distanced - otherwise inaccessible parts of the architecture seem more tangible and intimate. I particularly like the quirk that the distant caravan park is visible through the high windows.

In the high aerial view on the other hand - taken during a Historic Scotland sponsored flight in a Cessna 172 - the tops of the structures are as distanced as the everything else in the frame. We could say that this view - taken with a strong lens - is normalising, in that features are represented in broadly equal size. There is no possibility to focus upon foreground detail or compress the skyline into the background in the same way. Instead in this photograph it is necessary to include the sea cliffs in the bottom of the frame in order to give a hint of the site's coastal setting. The structures themselves are arranged more formally, almost akin to a measured isometric view. While this gives a more acurate impression of the site overall I think that this image would be somewhat less engaging if it wasn't for the long shadows and snow cover, which place it in a particular moment of time rather than in a technical drawing.

Linlithgow Palace, photograph taken from a kite aerial platform.
Brougham Castle, photograph taken from a light aircraft.
This second comparison shows a low altitude view of Linlithgow Palace, again taken by request from Historic Scotland, and a shot taken just last week from another light aircraft showing Brougham Castle near Penrith, Cumbria. The top image was taken with a very wide-angle lens and exemplifies the diverging vertical lines which often characterise the low altitude aerial view. As well as being graphically sriking, this gives a much better sense of depth and three-dimensional space which the site inhabits. When looking at a site of this scale from high altitude some of the ques for depth perception are missing; the effect of foreshortening and atmospheric perspective are both greatly reduced.

These two images demonstrate another significant difference. While the wide-angle low-level view can include the skyline, from the high-altitude oblique view, middle distance objects - the bridge and river in this case - can dominate the background instead. I have found that when composing photographs from a plane framing is far more of a challenge. Not only is the scene quickly changing as the aircraft passes by but the usual foreground-background structure is replaced with a more fluid juxtaposition of elements within the composition. This of course opens new possibilities in visually connecting features which perhaps share a narrative.

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