Aerial photographs have many uses and the phrase that a 'picture is worth a 1000 words' is never more true than for aerial photographs. They provide the landscape view and site context, the building blocks for broad-brush landscape characterisation and understanding the historic landscape. The bird's eye view is a powerful way of exploring sites and landscapes, and for certain types of sites (e.g. cropmarks) is the only effective way of discovering monuments and placing them on record. Beyond the archaeological uses for recording during primary reconnaissance, interpretation and mapping, they provide excellent materials for teaching and illustration.
The use of aerial photographs in archaeology has a history extending back more than 100 years and is recognised as one of the most effective ways of recording sites and landscapes. Archives of aerial photographs are a rich source for identifying otherwise unknown monuments and can provide unique records of landscapes and sites that have been changed or destroyed, while new aerial photography provides a means of recording during primary archaeological reconnaissance. Aerial photographs result from two ways of recording the ground, firstly routine survey to photograph a pre-defined area of land (e.g. area-coverage vertical, usually for planning/cartography/military intelligence) and secondly archaeological reconnaissance by an airborne observer who photographs objects seen and understood to be of interest.