Today on the blog we are taking to the skies to talk about aerial archaeology; the investigation of archaeological sites and landscapes from a higher altitude. There is nothing quite like having a bird’s eye view, and, when investigating archaeological sites or considering the archaeological potential of an area, one of the first things we look at is aerial imagery. For much of the 20th century aerial imagery was recorded via a plane, but in our modern era we have access to high quality satellite imagery and drone footage. Aerial archaeology is just another everyday tool in the archaeologist’s belt, and today we are going to go through a bit of background before diving into some local examples.
If we go back to the very beginning, on a small farm outside of Temuka, a humble Kiwi farmer was one of the first people to fly and land a powered heavier-than-air machine (Figure 1). I’m talking of course about Richard Pearse, who flew in 1902, nine months before the Wright Brothers – not that I am keeping score. While our friend ‘Bamboo Dick’ (yes that’s what they called him) didn’t take any photographs from his ‘monoplane’, his inventions and trials mark the beginning of flight in New Zealand – it would be rude not to give him a shout out.
Figure 1: Richard Pearse and his ‘monoplane’ forever remembered on a limited edition stamp and in our hearts (New Zealand Post, 1990).
Once people were up the air, it didn’t take long before the first aerial photographs were taken, including those of archaeological sites. To begin with this largely took place in Europe and America with iconic sites such as Stonehenge being among the first to be photographed from the air (Figure 2). In New Zealand things were a little bit slower, but by the 1920s aerial surveys were being completed in specific areas throughout the country. Within Christchurch, the 1920s aerials are pretty much limited to the coastline and the Port Hills. Unfortunately, we don’t have coverage of the CBD at this stage, but we do have a great view of Lyttelton. The quality is actually really good, and you can easily see the contours of the topography and individual buildings. But one of the most striking things we can see, is the development of the Lyttelton Port over the past 100 years (Figure 3).
Figure 2: Stone Henge from a hot air balloon 1906 (Renfrew and Bahn, 2012:78).
Figure 3: Above: Lyttelton Port late 1920s. Below: Modern aerial imagery (Canterbury Maps, 2023).
The 1940s, and the advent of World War Two, resulted in widespread systematic aerial surveys of Canterbury and wider New Zealand, including Christchurch’s CBD (Figure 4). Photos from this era and much of the 20th century are black and white, which is preferential for us as archaeologists. Black and white photos clearly show contours, shadows, and topography, especially if they are oblique (at an angle to the landscape). In contrast vertical photos are much better for understanding spatial layout and are handy for mapmaking (Figure 5).
Figure 4: Christchurch within the four avenues, early 1940s (Canterbury Maps, 2023).
Figure 5: The two types of aerial image – yes, I took this from my first-year textbook (Renfrew and Bahn, 2012: 79).
Further aerial surveys were completed throughout the 20th century, with all of New Zealand photographed by the 1950s (Jones 1996: 25). By the 1990s we even had colour! But don’t get too excited as the quality is terrible, I tend to avoid the photos from 1995-2004 altogether (Figure 6).
Figure 6: A very blurry, but coloured, Christchurch Cathedral (Canterbury Maps, 2023).
By the 1950s and 1960s, the systematic use of aerial photographs for archaeological purposes had commenced and there are a few early reports and articles that talk about this ‘new’ technology (Gorbey, 1967). However, in the world of aerial archaeology in New Zealand, one person in particular comes to mind – the late great Kevin Jones. Kevin made both nationally and internationally significant contributions to aerial archaeology. I even learnt about him and his contributions while studying at university (and was just a tad starstruck when I met him). His book Ngā Tohuwhenua Mai Te Rangi: A New Zealand Archaeology in Aerial Photography is nothing short of quality research and sheer beauty. It showcases New Zealand’s archaeology much more eloquently than I could ever dream to discuss in a blog. For anyone who wants to check it out, his book is available digitally here (https://nzetc.victoria.ac.nz/tm/scholarly/tei-JonTohu.html). Thank you for all of your mahi Kevin <3
Figure 7: A key text typically found on most archaeologist’s bookshelf.
Let’s look at some archaeology!
Perhaps the most iconic archaeological site type we have in New Zealand is the pā. Many pā, particularly in the North Island, have been photographed and surveyed from the air, as their earthwork features are stunning from this viewpoint (Figure 8). Cascading pits, tumbling terraces, and extensive earthworks really shine in oblique black and white photographs. While pā are more common up north, we do have some spectacular pā here in Canterbury, including those accessible to the public. One example is Ngā Niho Pā on the Kaikoura Peninsula (Figure 9). Its location against the Peninsula’s rocky edge provides both a natural defence and clear viewpoint along the coastline. Another example a little closer to Christchurch is Ōnawe Pā, located at the head of Akaroa Harbour (Figure 10). Its long thin neck provides a natural defensive feature, and from black and white aerials we can clearly see further defensive earthworks on the interior of the pā (Figure 11). Make sure you stop in to visit these sites on your next road trip, just remember to be respectful and follow any outlined tikanaga. And, of course, if you want to learn more about these places, check out some indigenous resources like the Kā Huru Manu: the Ngāi Tahu Cultural Atlas.
Figure 8: Cascading pits at Kohukete, one of the largest pā in the Hawkes Bay (Jones, 1996: 27).
Ngā Niho Pā on Kaikōura Peninsula. Strategically located against the steep hillslope. This pā is open to public access (Canterbury Maps, 2023).
Ōnawe Pā – using the environment to its advantage (Canterbury Maps, 2023).
Close up of Ōnawe Pā – can you see the defensive ditches? (Canterbury Maps, 2023).
Within the Christchurch CBD, most of what we see in aerial photography is buildings – no surprises there. But through aerial photographs we can see changes, additions, and demolitions, which is all useful information we need to understand the history of a site. Sometimes all we need to see is the roofline of a house to better understand how it has been added to over time (Figure 12). Sometimes all we have left to physically indicate a building ever existed is the footprint or the foundations (Figure 13, Figure 14, Figure 15). And sometimes you are just being nosey and stumble upon something a bit more interesting and uncommon than usual (Figure 16).
Figure 12: A cluster of late 19th century houses in Christchurch that were demolished after the Canterbury earthquakes. Can you see all those lean-tos? (Canterbury Maps, 2023).
Figure 13: At first glance you may think this was another pā but no! This is the site of Christchurch’s first (of three) quarantine Stations. It’s located over in Camp Bay and those are the former building platforms. The cemetery is located on the headland (Canterbury Maps, 2023).
Figure 14: The concrete foundations of ‘Mansion House’ in Cheviot (Canterbury Maps, 2023).
Figure 15: A photo of ‘Manion House’ in Cheviot c. 1890 (unknown, 1890).
Figure 16: Ripapa Island – former pā, former quarantine station (the second one), Russian Scare fort, WW1 and WW2 defence. What an over achiever (Canterbury Maps, 2023).
From the air we also see scars of the former landscape and environment. A good Christchurch example is Horseshoe Lake over in Shirley. The lake is a redundant and cut off loop of the adjacent Avon River (Figure 17). It would have likely been cut off following a flood event where the Avon changed course, leaving the lake behind. Other former or remnant river channels are visible in aerial imagery throughout Canterbury, and they attest to the dynamic nature of our braided river systems.
Another major scar we see is the impact of the Canterbury Earthquakes. A review of aerial imagery from after 2010 is a particularly sobering experience. Collapsed buildings, liquefaction, spilling bricks, and sheer chaos can be taken in from above. Many of the gaps left behind in the city still lay vacant today and if we move outward into suburbia the rise of the Red Zone resulted in the death of many neighbourhoods (Figure 18).
Figure 17: Horseshoe Lake (top centre) now isolated from the main body of the Avon River(Canterbury Maps, 2023).
Figure 18: The extensive Burwood Red Zone (Canterbury Maps, 2023).
In contrast we also see the birth of new towns like Pegasus Town, to the north of the city (Figure 19 and Figure 20). When comparing different decades of aerial imagery, it can feel like these new towns and subdivisions spring up overnight. They may seem like a major change, but in reality, it’s just another step in the urban growth of the region and the start of a new story.
Figure 19: The location of Pegasus Town prior to development in the mid 2000s. Woodend is tucked in the bottom left corner (Canterbury Maps, 2023).
Figure 20: Pegasus as it stands today (Canterbury Maps, 2023).
I could go on for hours showing off more sites and explaining the uses of aerial archaeology, but I am nearing my word count. So, lets park it for now and maybe we can come back again and share more finds from the sky in future. In the meantime, check out some historic aerial imagery and have a snoop! These resources are free and online. You never know what you will find!
Alana Kelly
References
Canterbury Maps, 2023. Canterbury Maps Viewer. [online] Available at: https://canterburymaps.govt.nz/
Gorbey, G. 1967. ‘Aerial Photography in New Zealand archaeology’, New Zealand Archaeological Association Newsletter, 10(4): 167-175.
Jones, K. 1996. ‘Aerial Archaeology in New Zealand Archaeology’, Australasian Historical Archaeology, 14: 25-33.
New Zealand Post, 1990. Heritage – the Achievers stamp issue. [Stamp]. Available at: https://teara.govt.nz/en/postage-stamp/6562/commemorating-new-zealands-first-flight
Renfrew, C. and Bahn, P. 2012. Archaeology: Theories, Methods, and Practice. 6th edn. London: Thames and Hudson.
Unknown, 1890. Mansion House, Cheviot Estate. [Photograph]. Available at: https://ndhadeliver.natlib.govt.nz/delivery/DeliveryManagerServlet?dps_pid=IE57788&dps_custom_att_1=emu Accessed March 2023.