Maps and Mapping at the Royal Commission: Putting the Past in its Place: a talk by Tom Pert

We were very grateful to Tom for standing at quite short notice on 16th March 2017, to give this talk in place of the previously advertised event. Tom has worked for the Royal Commission on the Ancient and Historical Monuments of Wales (RC) since 2002, initially as GIS and Archaeological Mapping Officer, more recently as Online Development Manager. He leads on Innovation for the Welsh Government’s People’s Collection Wales programme, and has been at the forefront in the development and application of new services that encourage the general public’s use and enhancement of historic data, including the use of crowd-sourcing, location and proximity based services.

Since its establishment in 1908, the RC has been recording archaeological and historic sites and monuments. The role of the Commission both as a public archive of maps, and as a map producing body supplying map depictions of archaeological sites to the Ordnance Survey (OS), is unique to Wales. The collection comprises about 30,000 large scale OS maps covering the whole of Wales, at 6″ and 25″ to the mile. The location of every known site of historical importance in Wales is recorded by the RC, with the grid reference being the key mapping identifier. Their application of the detailed information allows them to produce maps showing very specific elements, such as a map of battle sites. Also from the OS is a collection of 1:500 scale town plans, covering 26 towns including Aberystwyth, Newtown and Welshpool, dating from the mid 1860s.

The several aerial photographic collections, totalling 500,000 images, including vertical and oblique photography, add a hugely significant dimension to the RC’s site discovery and recording. The photographs originate from the RC’s own flying programme and from other major sources such as the OS, Royal Air Force, and the Aerofilms collection (1919-1956) (see for more information). The RC continues to add new aerial images captured by their Air Survey Officer, Dr Toby Driver. In certain conditions such as a light snow covering or a heavy frost, drought, or a low angle of the sun, the landscape can reveal previously unrecognised earthworks or the outlines of ancient communities. A recent discovery is the Pen-yr-Allt Iron Age hill fort near the Llanidloes golf course. Aerial photography captures the evidence for archaeologists and cartographers to investigate and record. The photography also extends beyond dry land in order to map ship wrecks in the coastal waters of Wales, and a new Heritage Lottery Funded project at the RC will see this activity include the mapping of the results of WW1 U-boat activity around the coast of Wales.

Another aspect of mapping at the RC is identifying those archaeological sites that may be in danger from the effects of climate change, such as rising sea levels. By combining survey data and site listings, the RC is able to provide the OS and other agencies with the information they need to look at how to give these sites better protection.

New techniques and technologies such as RADAR and LiDAR (using radio waves and laser beams), drones and satellites, are now used to enhance survey data collection, and have resulted in the discovery and identification of new archaeological sites, for example recently during a survey of the island of Skomer. From the data collected, it is then possible to use 3D visualisation techniques, stripping away vegetation or modern buildings, to reveal graphically the archaeological remains below.

Contributions by members of the public to various projects have assisted the RC in various ways to achieve what would be impossible if they depended on paid staff alone. The ‘Cymru 1900’ project was assisted by volunteers transcribing placenames onto a map dated 1900 to create a Wales-wide gazetteer, which will be a mine of information for researchers. The top 10 volunteers contributed about 450,000 placenames between them, with over 200,000 being contributed by just one individual. Such is its success that the project has now widened to cover the whole of Great Britain as ‘GB1900’. ‘Cynefin’ ( is an ambitious project to digitise all the tithe maps of Wales and is founded on the National Library of Wales’ near complete collection of 1840s tithe maps. Volunteers have almost completed the geo-referencing (placing markers on the tithe map and the OS map to fix the location of a specific point, in order to make current maps as geographically accurate as possible) and transcribing places and field names on the tithe map into the database, which will be available to search through the Cynefin website.

For more information on these fascinating projects, visit the RC’s website: