Assessing the Accuracy of The Map of the Prefectural Capital of 1261 Using Geographic Information Systems
This paper explores the application of geographic information systems (GIS) in the evaluation of the accuracy of early maps through a case study of The Map of the Prefectural Capital of 1261. The evaluation of the accuracy of early maps is an important aspect of the study of the history of cartography, but no standard methodology has been generally accepted. The purpose of this paper is to assess the positional accuracy and the relative relations of the spatial objects on The Map of the Prefectural Capital using GIS. The procedure of the study includes identification of locations of the points and features of The Map of the Prefectural Capital on a modern base map, digitization of the early map and the modern base map, overlays of the digitized early map and modern base map, and an analysis of the absolute and relative distortion of the early map. The results of the analysis show that The Map of the Prefectural Capital of 1261 is reasonably accurate considering the technical ability of the thirteenth century, although it contains a considerable amount of positional displacement. In contrast to the amount of positional displacement, the relative relations among the objects are depicted much more precisely.