While maps are usually considered an output from GIS, they can also be used as an input. Such is the case with this colorful map of “soil capability for agriculture,” which was produced during the ambitious Canada Land Inventory, a comprehensive survey of Canada’s 260 million hectares of land, beginning in 1963 and continuing for over 30 years.
It’s doubtful that a computer was used to produce the soil map here. Instead, different features in the map, such as the color-coded soil classes, would have been digitized, and then saved in a computer as retrievable geospatial data. “The resulting data,” a 1965 report by the Canada Land Inventory noted, “could be made available as computer mapping input data and could be published as required.” This notion—that maps could be published as required—represented a profound change in the logics of mapmaking, as production could become more flexible and on-demand, as opposed to the more static publishing technologies of earlier cartography.