After more than 100 years of aerial photography there are an amazing variety of images available for study in the National Monuments Record and other collections as well as through sources now available over the web. Looking at a wide range of photographs from different years will reveal different information as well as giving a perspective on changing land-use and preservation of sites.
When undertaking an air photo investigation it is important to look at all of the available aerial photographs, both verticals and obliques. This can give you views of sites from various angles, under different conditions and over a period of several years helping to build up a more complete understanding of the historical landscape.
Archive photography may show an archaeological site preserved in a better condition than it now survives, or may simply be the only source of information because a site has been destroyed or was only fleetingly visible as a cropmark in exceptional drought conditions.
Two principal aerial photograph collections in England are held by English Heritage’s National Monuments Record (NMR) and Cambridge University’s Unit for Landscape Modelling (ULM). They include extensive collections of historic vertical aerial photographs and specialist oblique archaeological and architectural photographs. Detailed archaeological aerial survey work and casework should ideally involve consultation of these primary collections. A range of more recent digital imagery for the whole country is also available to view on various websites.
County-based Historic Environment Records (HERs) will normally be able to offer advice on the availability of local collections - sometimes held within the HER. These usually comprise a limited range of vertical photographs and some specialist oblique photographs. The National Association of Aerial Photographic Libraries (NAPLIB) was wound up early in 2008, but its directory still offers a useful starting point for identifying possible sources of images. 'NAPLIB 1999 Directory of Aerial Photographic Collections in the United Kingdom (2nd Edition)'.
National Monuments Record (NMR)
The NMR’s collection consists of 2.6 million vertical and oblique images. The vertical collection comprises reconnaissance and survey photography and covers the whole of England from the 1930’s to the present day. While most of the collection was flown by the RAF, other sources include the Ordnance Survey, Meridian Airmaps Limited and the recently acquired Aerofilms collection.
The oblique photographs fall into three main collections:
- The military oblique collection was taken by the RAF and dates from 1939 to 1960.
- The specialist oblique collection was produced by a number of specialist fliers, including English Heritage, and dates from the 1960s to the present day. Though initially the focus was on ‘traditional’ archaeology, the collection has diversified to include all elements of the man-made landscape.
- The Aerofilms collection was recently acquired by English Heritage in partnership with Royal Commissions on the Ancient and Historical Monuments of Wales and Scotland. It includes an additional 1.26 million negatives and over 2,000 albums dating from 1919 to 2006 (currently being catalogued). The collection is very varied including urban, suburban, rural, coastal and industrial scenes.
Other UK collections
Cambridge University’s Unit for Landscape Modelling (ULM): The catalogue of photographs held in the Cambridge collection (commonly known as CUCAP) can be queried on-line via a simple geographic information system (GIS), but the images themselves are not currently available online.
Collections covering Scotland and Wales, comparable with that of the English National Monuments Record, are curated by the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) and the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW).
US and German (Luftwaffe) Second World War coverage of the UK and other areas is held in the United States National archives.
On the Web
A number of online sources of satellite and aerial imagery are now available on the internet including GoogleEarth, GoogleMaps, and Bing, providing easy access to recent aerial images of the whole of England.
Satellite and aerial imagery resources include:
Only a very small proportion of the NMR collection of aerial photographs is currently available online.