This week I looked at how 16th Century London could be mapped in order to provide geographical reference to other urban data from other sources. To do this, they needed to combine maps dating from different centuries so that they could accurately georeference data points.
The oldest map they used was illustrated by John Rocque in 1746, and is considered to be the first reliable map of London. It originally came in 24 different ‘plates’ and was required to be pieced together by hand and using photoshop. During the copying of the original map and printing process cause small variations in the edges of the maps, “Minute magnifications” needed to be made in order for the pieces to fit together. For this reason, this map reflects the points of view of both Rocque and the researchers. While indeed the researchers strived to be as impartial as possible when making assumptions about how map edges should align, there is an unavoidable human choice factor. Obviously, however, this map most strongly reflects the assumptions and points of view of Rocque.
In order to provide accurate modern scale to the map, it needed to be georeferenced using an officially accurate Ordinance Survey map. OS was the first organisation to accurately map areas to scale and produce detailed maps of Britain. Soon after the birth of Ordinance Survey, a to-scale map of London had been produced. Yet the OS map used during the georeferencing was from 1869-1880. Using major intersections of lasting roads, the research team was able to overlay the maps onto each other. Owing to the combination of Rocque’s poor instrumentation and measurement and imperfections in the researcher’s printing process, Rocque’s map ended up being warped. While this first appears to be obscure, it is the most accurate depiction of London using Rockies illustration.
This project was particularly impressive to me because I was born and raised in London and was eager to try to find some of my favourite contemporary locations and see how they appeared almost 500 years ago. My high school is on the map, and even though my house is in (West) Central London, it is unfortunately excluded. Thanks, Rocque!