City maps of Yedo, the capital of the recent times of Japan, are important materials for social study of recent city formation as well as history and geography. It is, however, very difficult to compare them with each other and make use of them as materials of social science, because most of them were drawn manually and without accurate measurements. In this project, some methods for processing them in a uniform manner on computers were developed and usefulness of the methods were confirmed.
1. Each of the maps of Yedo was divided into rectangular blocks and coordinates of their verteces were input into a computer. Modern maps of Tokyo were also stored in the computer in a similar way. Then blocks of each map of Yedo and those of a modern map were related by means of projective transformation from projective geometry. Parameters of projective transformation enable Yedo maps to be remapped into accurate maps.
2. Using the parameters of projective transformation, a method of expressing skews in orientation and distance of the blocks on maps of Yedo by shape of rectangles which are remapped into unit squares on accurate maps was derived.
3. Based on these methods a database of city maps of Yedo was developed. With the database we can look over target maps in a superimposed mode or a single map mode.
4. It has been concluded that hypermedia structure is adequate for a database of materials concerning Yedo maps and related data.