Measures the extent to which the feature can be observed, relative to other spaces in the sampled area. The full scene was sampled at regular points every 500m. A viewshed was run for each of these points, and the viewsheds were then combined, resulting in a raster that expressed the region's overall exposure. Each site was then sampled at points spaced at 15m intervals, The exposure value was determined for each point and these values were averaged to provide the exposure value for the feature.