Archaeologists have always used tools invented for other purposes. Our ‘signature’ tool, the trowel, was designed for brick-laying; our hoes, mattocks, shovels and wheelbarrows are gardening tools; and I doubt the inventors of the JCB dreamt that with the right bucket and a skilled operator their heavy earth-moving equipment could delicately strip off a few tens-of-centimetres of topsoil to cleanly expose archaeology in the subsoil beneath. What is true of physical tools is also true of technological ones; total stations and computer-aided design were created for construction; satellite imagery had its genesis in espionage; GIS were first used by geographers. Even our theoretical and methodological foundations are often borrowed from others. As archaeologists we specialise in taking something made for something else, and tweaking it to answer our questions. Adapting an existing tool to answer our research questions is as archaeological as brushing dirt from a precious artefact and, as I recently discovered, is widely applicable to a variety of situations beyond the excavation, lab or library.
Seeking petrol
At the time of writing, the UK is currently experiencing a temporary fuel shortage, resulting from a combination of panic-buying and a shortage in HGV drivers. I live in a suburban area, but public transport is limited and I have a pre-schooler, so I have always done a modest amount of driving. The fuel shortage caught us unawares with limited petrol in the car and after a few days of taking my little one to school we were running seriously short. At this time fuel deliveries were still being made, but the number of people seeking fuel and the intermittent nature of the deliveries meant that it was impossible to know which petrol station would have fuel. I needed to find a way to determine exactly which petrol station might have what I needed before I left. Where could I find real-time information on which petrol stations had fuel? How could I locate the closest one?
Real-time feedback in Google maps
Thanks to years of archaeological research, I have a long history of looking at maps and satellite imagery and I’m used to combining data, maps and visual imagery to address research questions. So when I was faced with a very real problem my brain automatically thought along the same lines. Since I was looking for the closest petrol station with fuel, the problem was obviously a question of mapping. Google maps is one of the most powerful mapping tools available for simple tasks and offers real-time information, it was a sensible place to start looking for a solution.
When teaching basic GIS I often use Google maps as an example of a deceptively simple but immensely powerful GIS. Behind the Google maps interface is an incredibly complex programme collating vast quantities of data, from satellite imagery and road maps, to data about speed limits and real-time information about traffic movements. Despite this complexity and vast processing power, it appears simple to us because the interface places substantial limits on what we can do with it; see a map of the area around us, search for a location, navigate from one place to another, or find a simple amenity, like a petrol station. Google Maps is immensely powerful but setup to be used in certain specific ways. It contains the locations of nearby petrol stations (as in the image above) and real-time traffic information (image below), but its not setup to find petrol stations with fuel. If I wanted do that I would need use it in a way its designers had never intended. I would need to adapt this tool to access the data I needed, just like generations of archaeologists before.
Adapting the tools
Adapting the data from Google Maps to answer my question necessitated current background knowledge of the situation and its impact on my society. The one thing everyone in any urban or suburban area knows about the petrol shortage is that any petrol station with fuel rapidly creates a jam along the adjacent road as people queue up to get fuel and block the road. So I combined the petrol station locations with the traffic information to identify petrol stations with queues outside. Since people don’t queue outside a petrol station without fuel, those with queues must have fuel. In the image to the right Tesco Petrol Station and the West Street BP to the right of the map just above the ‘Southend’ label, both have queues outside. The Shell to the right of Tesco does not. We promptly went to the West Street BP and fuelled-up without difficulty.
‘Improper use may cause damage!’
As when using any tool in a way its creators did not intend, a certain amount of local knowledge, experience and common sense is required. In the image to the right the BP with a Wild Bean Cafe in the bottom left also has queues shown to the west of it, but I can’t be sure those indicate it has petrol. It’s on the A13 and close to a junction. The A13 is a major road that is often slow and can have queues and jams almost anywhere on it for any reason, and the traffic lights often produce short local jams like those shown in the image. So if I was really desperate to go straight to a petrol station with fuel, seek out queues at petrol stations on a minor roads some distance from intersections. The BP petrol station on West Street, Prittlewell, is an excellent example. The West Street BP is centre right, just above the ‘Southend’ label in the image above right. When I checked traffic information against petrol stations I found a dark red tail leading away from the West Street BP (centre right in the image below). West Street is not a major road and the BP is not close to a major intersection. The only likely reason there’s a queue leading straight to that petrol station at 8pm is that those people are waiting for fuel.
Checks and balances
Its possible to double-check that a petrol station has fuel using the powerful statistics held in Google maps. At the time of writing it is 1pm on a sunny weekday. There should not be a lot of unusual traffic or unexpected jams that are unrelated to fuel queues and might confuse me, but if it was rush-hour I’d have to be more careful. Checking the petrol situation at the present (image above) it seems that the Tesco Petrol Station and Shell in the centre right of the image have fuel, while the Esso MFG Kent Elms does not.
I can confirm that the traffic information reflects queues for fuel rather than any other traffic incident by checking the real-time statistics in Google Maps (this was Paul Barrett’s idea). If you click on the little marker balloon for a likely petrol station and scroll down, there’s a little graph showing popular times. If the queue on the traffic information is for fuel, the graph should show that the petrol station is currently ‘busier than usual’. If we check on the Tesco Petrol Station for now 1pm on 4 October 2021, we find it is ‘busier than usual’ (image above left), confirming the evidence of the traffic information, that showed a queue outside it. This contrasts quite nicely with the BP on West Street, which is now running out or is out of fuel and is therefore ‘less busy than usual’ (image above right).
Adapting and mis-using tools
Aside from being an interesting use of an incredibly powerful free GIS, why is my solution to a personal fuel crisis of archaeological or Egyptological significance? I believe there are two reasons. The real-world value of humanities and social science disciplines like archaeology and Egyptology are often questioned and those who study them expected to explain how their supposedly arcane subject prepares them for the real world of work. I developed this particular method of solving my real-world fuel shortage problem because of my long history of looking at maps and satellite imagery and combining various sources of data and visual imagery to address research questions. While students learn many valuable skills studying archaeology or Egyptology, the ability to marshal varied sources of data in textual, statistical and visual formats; and judiciously adapt tools for new purposes, is highly valuable in many professions.
Secondly, my method of finding petrol stations with fuel follows the same model of adaptation that is common in archaeology and Egyptology. I took an existing, common tool (Google Maps) and combined two established features of that tool (real-time traffic information and the local search function) with specific cultural knowledge (that petrol stations with fuel attract queues) to extract information on which petrol stations were likely to have fuel. I improved the rigour of my method with additional background cultural and cartographic knowledge (of the main roads and traffic hotspots) and checked it against an independent dataset (Google Maps real-time statistics on how busy locations are). The result is an efficient and effective method of obtaining information I did not previously have direct access to but which was present in existing datasets, all without developing new software or diagnostic tools. For me this is what GIS, landscape and archaeological research is all about!
Scribe in the House of Life: Hannah Pethen Ph.D. 