Historical data and archaeology

Clearly there is a lot of really interesting historical data available, but how exactly can archaeologists use it in their work? Let’s look at some examples!

Site prospection

Historical data can be invaluable for archaeologists when they are looking for new sites.

As it dates to a point from before urban and agriculture expansion, sites are often easier to identify on Corona imagery than when using modern satellite imagery. This makes Corona a fantastic tool for finding new sites.

_{Ancient settlement mounds are much clearer on the Corona image from northeast Syria than the modern Sentinel-2 image. Courtesy of the USGS and ESA.}

Sometimes old maps include archaeological features that have since been destroyed, or simply forgotten about.

_{Map of part of Ajlun, Jordan from 1964. Cairn tombs and stone enclosures have been included on the map. Army Map Service, Series K737, Sheet 3454-I, 1964.}

In other cases, archaeological sites were recorded on old maps unintentionally. For example, settlement and burial mounds may have been recorded as contours or natural hills with the surveyors having had no idea that they were recording archaeology! This often happens when maps are produced or updated using aerial photography, as the mapmakers may not have seen the features on the ground. By (re-)interpreting the data recorded on historical maps, archaeologists can find previously unknown sites.

_{Tells (settlement mounds) recorded on a World War One map of Kirkuk, Iraq from 1917. Mesopotamian Expeditionary Force Survey Party, map T.C. 147, 1917.}

Landscape archaeology

Historical maps and imagery are invaluable to landscape archaeologists for better understanding the relationship between sites and the natural environment. Such data can be used to see how landscapes looked in the recent past – closer to how past populations would have seen them.

_{This map of Dubai from 1953 gives a much better idea of the natural landscape of the area than modern satellite imagery or maps which are dominated by extreme development, landscaping and construction. Army Map Service, Series K502, Sheet NG 40-9, 1953.}

Historical data can also help to better understand traditional settlement patterns. Looking at the distribution of farms and settlements on modern imagery can hinder archaeologists from mapping where it was possible to live and farm in the past. However, old maps and imagery can act as a guide for understanding much older settlement patterns.

_{Corona (left) and Sentinel-2 (right) image of Shinas, Oman. The distribution of agriculture and settlement has completely changed since 1970 as the arrival of diesel water pumps has allowed areas further inland to be farmed. The geographical constraints reflected in the 1970 image are those that would have faced populations since the Bronze Age, so the pre-modern settlement patterns are very relevant to archaeologists! Courtesy of the USGS and ESA.}

Heritage protection

This historical data can also be used to help understand the threats facing archaeological sites, and to help protect them.

As we have already seen, maps and historical imagery can be used to find new (or forgotten) archaeological sites. In many cases these will need to be recorded and protected before they are disturbed or destroyed. It is also important to record sites that appear on old maps but that have since been destroyed, as this will help heritage professionals and agencies to better understand their archaeological dataset as a whole.

_{The expansion of the city of Baghdad since 1950 has led to the destruction of a great number of archaeological sites, like these shown in a 1958 map of the city (top) that are clearly overbuilt in the 2020 Sentinel-2 imagery (below). Courtesy of ESA, and Army Map Service, Series K941, Baghdad, 1958.}

Historical data can also help those working to protect archaeology to gain a better understanding of the challenges facing sites. Being able to observe the extent and direction of agricultural and urban expansion in recent times, allows heritage professionals to better predict future disturbances.

_{This 1960s Corona imagery and modern Sentinel-2 show how the southern Iraqi marshes (the dark areas) have shrunk in the last fifty years. This trajectory suggests that the drying out and erosion of archaeological sites in the marshes is likely to be a major future concern. Courtesy of the USGS and ESA.}

_{How might historical data be useful in your area of interest?}

Now we have learnt a bit about the use of historical maps and imagery in archaeology let’s start working with them ourselves!