An aerial photograph shows much more than archaeological features and by reading that information, especially the non-archaeological elements, we are often able to place an archaeological site in its contemporary context (such as a location on locally high ground) as well as a modern one. Photo reading of this kind is one of the early stages of examining aerial photographs and is a useful time to discuss findings with colleagues. Discussion, reflection and constant questioning are necessary to improve the skills and knowledge of a photo interpreter.
The aim of photo interpretation is to identify, depict and describe features of archaeological interest as well as any others that may be relevant to our understanding of them. Our interpretations are produced for a reason and different reasons are likely to produce differences in what is interpreted and eventually mapped. Reasons could include study of a site or area for a research project, updating a county or national record, preparing a map to be used in collaboration with a field walking programme, or to guide excavation prior to development. Mapping at different scales will also vary the end product â€“ some features, for example, cannot accurately be shown at small scales and on large scale maps we may expect a lot of detail. Context may be shown by mapping natural and recent features and work done prior to excavation may attempt to show and classify anything that will be seen once topsoil has been removed. Thus we can have a variety of interpretations that serve different archaeological purposes.