Historical Basemaps

Up until now, I have been working with relatively generic contemporary baselayer maps. But I was interested to see how different certain older maps might be, given some of the political upheaval in South America in the past 80 years. Of course, however, I first had to get lost in the fabulousness of the historical maps themselves.

For example (and extremely apropos), in 1942 Ernest Dudley Chase published what was called the “Good Neighbor Pictorial Map of South America.” While one digital collection explains that this was meant to offer up “a positive message of solidarity between South America and the U.S.”, another indicates that it was used by the Moore-McCormick Lines. This was in fact the ocean liner company that American Ballet Caravan used between New York and Rio at the start of their tour.


Other maps were created for different uses, such as this 1942 physical-political classroom map, designed for viewing from up to 40 feet away (and used in UC Berkeley’s Department of Geography). For the moment, I have started with a Rand McNally road map from 1941.

Unfortunately none of the pre-referenced maps in the extensive David Rumsey Map Collection corresponded closely enough to locations and dates. But the collection does allow users to contribute their own georeferencing, so I started working on the road map with some clumsy correlations of my own. Mike then took the next step to develop a Mollweide projection, that he then rubbersheeted to match some prominent cities. He also wrote me out a tutorial in the process.

Screen Shot 2015-07-28 at 9.37.43 AMThe historical maps do more than simply provide an accurate baselayer. For example, I have been wondering about some of the empty spaces on the maps that I have been creating so far. In other words, where didn’t the tour go and why? Or why choose these particular cities? I have been searching for other open datasets pertaining to South America in 1941, which might help answer such questions via population, GDP, etc. However, looking at the 1941 atlas, it is conspicuous that the most dominant lines and therefore the largest roads on the map trace out almost exactly the path taken by American Ballet Caravan (even though the company itself often traveled via other means). I’ve turned on the breadcrumbs in the cumulative animation, so that this pattern is visible.