Metadata detail: AI Predicted Historic Woodlands, Wales (OS County Series – 1843-1893)

Identification

Title

AI Predicted Historic Woodlands, Wales (OS County Series – 1843-1893)

Abstract

This is an experimental dataset comprising of areas of woodland as depicted on the Ordnance Survey (OS) 1:2500 (or 25") County Series Historic Mapping. For this dataset, woodland was defined as any area with a minimum width of 20m and minimum area of 0.5 ha that contained the symbols Wood, Mixed Wood, Fir, Bush, Orchard or Osiers, as depicted in the map key.

These estimates are produced using an AI computer vision model called mask-rcnn. This model is trained on a small sample of manually labelled data which contains different areas of woodland as described above. The model learns the key features associated with woodland, such as the distribution and pattern of pixels. The model is then applied to predict areas of woodland by identifying the same features on unseen data across the Wales.

As this technique involves predictive modelling, there are uncertainties with the dataset. We have attempted to mitigate these by adding additional validation steps on the model predictions, however there is still a risk of the model mis-predicting, or not identifying, areas of woodland on the map.

Ordnance Survey (OS) 1:2500 (or 25") County Series 1843-1893 Historic Mapping did not survey extensive upland areas and so cannot be included in this dataset.

Instead, we recommend this dataset should be used to indicate the likelihood of woodland existing in different areas in Wales during this period. As well as the boundaries of the wooded areas, the model also provides a probability score which represents the model’s confidence in that area containing woodland.

This dataset is created using a different experimental methodology to other historic woodland outputs. For example, the Ancient Woodland Inventory was created by manually reviewing and comparing the presence of woodland on Ordnance Survey (OS) 1:2500 (or 25") County Series 1843-1893 Historic maps to the National Forest Inventory, so only areas of woodland that were still present as woodland in 2011 were included.

If you have any feedback on this experimental dataset and how it might be improved, please contact datascienceunit@gov.wales.

Licence