Fig. 9

Spatial extent (grey shaded area) of clean-up zones used for geospatial clean-up modelling. North at top. Aerial imagery sources: Esri, DigitalGlobe, GeoEye, i-cubed, USDA FSA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community