Aerial photographs are useful for locating and analysing rural settlements and landscapes because they often capture details of archaeological remains that are not recorded on maps and which are too subtle to see at ground level. Buildings, track-ways, field systems and rig-and-furrow cultivation are among the features that can be clearly detected from the air.
There are two types of aerial photographs: vertical and oblique. Vertical photographs give you a real birds-eye view of landscapes, as they are taken looking directly (vertically) down at the ground below. Oblique photographs are taken at an angle and are normally focussed on particular sites or other features.
If possible, it is a good idea to look at aerial photographs taken at different periods (1940s photographs are useful for identifying sites on ground which was later developed for agriculture or forestry), and at different times of the year (crop marks show up best in late summer, whilst rig and furrow, and other earthworks show up well in slight snow and low light).
It is also a good idea to look at aerial photographs in conjunction with a map of the area you are interested in. You should always follow this up by checking any features on the ground.
There are several ways to access aerial photograph collections:
RCAHMS holds a large collection of vertical and oblique aerial photographs of all of Scotland, dating from the 1940s to the present day, which you can look at in the RCAHMS search room.
Vertical aerial photography is held within the National Collection of Aerial Photography. An appointment is required to guarantee a workstation and the availability of staff to explain the finding aids and to retrieve photographs for you. To request an appointment, please complete the booking form.
Copies of vertical aerial photographs can be ordered online here.
Oblique aerial photographs taken by RCAHMS are arranged geographically on open shelves in the search room. They are easy to locate and navigate, and appointments are not required. Recent oblique photographs are also available online when searching for sites via Canmore.
Local Sites and Monument Records also hold copies of the earlier (1940s) RAF vertical photos, and some have their own collections of oblique aerial photographs.
Google Earth is a website which contains worldwide coverage of recent aerial photographs. Some parts of Scotland have excellent coverage at large scale, allowing you to zoom right in to view fields and buildings. Other parts of the country (particularly upland areas) have poorer coverage. The site is free - but you need to download the Google Earth software from the web.
Live Local is a website which contains worldwide coverage of recent aerial photographs. Like Google Earth, some parts of Scotland have excellent coverage at large scale, but other parts of the country (particularly upland areas) have poorer coverage. The site is free and can be used direct from the internet - no need to download anything.