Over the last year Geoger has been working with researchers at Wytham Woods (the Oxford University research wood, to the west of the city) to investigate the utility of LiDAR data for uncovering archaeological features – specifically, the remains of a network of World War 1 training trenches. The work started with the use of some raw LiDAR data and although some great visuals and interesting information could be derived from it, the trench system could not be seen in the data. The images below demonstrate just how impressive the quality of that initial data was, and the types of processing that could be implemented. Click on any of the images in this blog post to see a larger version.
In September 2015 the Environment Agency made its LiDAR derived elevation datasets open-access. This meant that anyone can search for, download and use the elevation data for any purpose, under the terms of the Open Government Licence (OGL) (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).
For this project, Geoger acquired datasets relating to 1 metre spatial resolution digital terrain models, as shown in the images below. The terrain data was then processed using hill-shade algorithms with various different parameters to highlight the underlying features in the data.
As already stated, the project team were specifically looking for evidence of a practice trench system which was used during World War I to train soldiers about to be sent out to fight on the continent. Evidence, both anecdotal and photographic, exist for the trenches. When the Environment Agency collected open LiDAR data was interrogated it was clear that there were features visible that matched the original trench system. The images below show the trench system as seen in the LiDAR data, an aerial photograph from the end of the First World War (Nov 1918) and the condition of the trench system after the Second World War (1946).
Two field visits were undertaken in the woods in late 2015 and early 2016 to verify the information that was extracted from the LiDAR data. The majority of the original trench system (as shown on the 1918 aerial view) is still visible on the ground, if you know where to look and what you are looking for. Some areas are easier to see than others, and the following selection of photographs from the field visits capture the most obvious trench remains. This has been a fascinating project to be involved with and shows the power of opening up datasets so that more can be done with the data.
Data statements: 1918 aerial photograph – Copyright: The Imperial War Museum; 1946 aerial photograph – owned and supplied by the Wytham Woods conservator; Ordnance Survey data: Contains OS data © Crown copyright [and database right] (2015); Environment Agency LiDAR derived elevation data: Contains public sector information licensed under the Open Government Licence v3.0.