The generalised land use was created from 1954 aerial imagery (2.5m) available from the University of Toronto map library (resource here). These images were georeferenced and areas were clipped out. While not as exact as newer GLU years, it provides a useful historical view of Peel County before its explosive growth in the following decades.
The shoreline of Peel was cut along the shoreline as it was in the 1954 imagery, which predated some of the heavy industrial land uses that reshaped the shore (for example, Lakeview Generating Station). The outer boundary is also different than the present-day boundary, as there were various changes to the boundary when Peel County was converted into Peel Region in 1974 and subsequent land exchanges took place with neighbouring municipalities such as Orangeville and Halton.