MapAnalyst - A digital tool for the analysis of the planimetric accuracy of historical maps

Modern digital techniques have the potential to greatly simplify the analysis and visualization of geometric properties of historical maps. This paper first outlines the purpose and goals of an analysis of a historical map’s planimetric accuracy, and identifies possible sources for geometrical imprecision. It then treats important considerations that the map historian should keep in mind, when transforming two sets of control points into a common coordinate system, which is a prerequisite to the generation of most accuracy visualizations. Important aspects for publishing accuracy analysis results are listed in order to guarantee the comparability of the results. MapAnalyst is then presented, a new user-friendly software application for the automatic generation of accuracy visualizations. Using the freely available MapAnalyst software, the map historian identifies complementary sets of control points on the historical map and a modern reference map. MapAnalyst then automatically generates a variety of visualizations illustrating the map’s planimetric accuracy. The paper concludes with ideas for new visualization techniques that could assist the map historian to more easily grasp the geometric characteristics of historical maps.