Premodern City Layouts Drawn on Published Maps: A Comparative Analysis of Edo, Osaka, and Kyoto
Museums, libraries, and other public research organizations have been creating digital archives of historical maps for some time. Initially, more work was required to archive historical maps than written documents, as they needed to be imaged in sections and then recombined. However, recent improvements in imaging technology and information devices have made it comparatively easy to create digital archives. In recent years, it has even become possible to view and download digital images of historical maps from sites run by the organizations possessing these maps, as well as from cross-searchable portal sites such as Old Maps Online (https://www.oldmapsonline.org) and Map Warper (https://mapwarper.net).These portal sites provide terrestrial georeferencing functionality, in which historical maps are superimposed on a projected coordinate system. This allows the sharing of geometrically corrected historical maps and images, as well as linking table information for control points created during the georeferencing process. As progress is made creating and publishing digital archives of these historical maps, it will become increasingly important to increase both the depth and number of methodologies used to analyze historical maps using GIS.In this study, I make use of image data from historical maps that have been geometrically corrected as well as control points created during the georeferencing process to conduct a GIS analysis of historicalmaps of several cities. My specific goal in this study is to analyze historical maps published for Edo, Osaka, and Kyoto, in order to quantitatively reveal differences in the shapes of cities drawn using the unique layouts of historical maps, which differ from modern projected coordinate systems (Table 1).