Using remote sensing in archaeology

Satellite data allows archaeologists to study vast areas much more efficiently than when they conduct fieldwork on the ground. It can also be done from anywhere in the world, without the cost and effort of visiting a site or study area. This can be particularly important when studying sites in areas where it may be too dangerous or politically difficult to conduct fieldwork. The fact that satellite imagery is regularly updated also makes it much easier to study changes to archaeological sites over time – and even to locate sites that are now destroyed. Remote sensing is therefore used widely in archaeology to locate, research, monitor and protect sites.

_{Many archaeological sites have been flooded in the last fifty years with the creation of dams like this one in northern Iraq. Notice the dam in the modern image – only the tallest hills within the valley remain above the level of the reservoir. Using historical satellite imagery, we can map the location of lost sites. Courtesy of the USGS and the Centre for Advanced Spatial Technologies (CAST), and ESA.}

Using remote sensing does, however, introduce a new set of challenges:

• Archaeological sites appear very differently in satellite imagery than they appear on the ground. Accurately interpreting the imagery takes extra experience – you have to know about the archaeology and understand satellite imagery! For this reason, it is important for archaeologists to verify their findings on the ground whenever possible.
• Remote sensing often involves specialist computer software which is not always easy to operate or learn.
• A good internet connection is usually required to find and download satellite imagery or other data, this can also take-up quite a lot of computer storage space.
• The quality of the available data can vary greatly across different regions of the planet, so identifying the most appropriate imagery for a specific task, and then locating and obtaining it can be difficult.

These are just some of the problems that we sometimes encounter using remote sensing in archaeology. But don’t worry! This course will help you learn how to overcome some of these challenges.

It is also important that an archaeologist picks the right remote sensing tool for the job. The best imagery or technique to use depends partly on the nature of the archaeology. For example, it is much easier to see a megalithic stone circle on a satellite image than a scatter of pottery! The climate and environment being studied are also important factors: most archaeological sites and features will be easier to identify in an open rocky desert than a dense forest. The level of cloud cover, the type and extent of vegetation, the depth of soil and the nature of the local geology can all contribute to the degree to which archaeological features or landscapes are easy (or hard) to see.

_{Looking for ancient settlements using remote sensing might look very different depending if you are working in the hills and plains of northern Iraq or the marshes of the south! Courtesy of ESA.}

_{Think about your own area of interest and the types of sites you might come across. What kinds of problems do you think you might encounter looking for archaeological sites using remote sensing? What advantages do you have?}

Although archaeologists use remote sensing for a wide range of applications, they can be broadly grouped into three areas: archaeological prospection; landscape archaeology; and heritage protection. Next, we will explore these three topics together!