Abstract
The discovery in the cartographic collections of the Faculty of Geography and Regional Studies at the University of Warsaw of an original map by Charles Dupin – the first choropleth map – provided an opportunity to conduct a closer methodological analysis of the map and to investigate the subsequent development of this presentation method during the first half of 19th century. From relatively early on, the accepted principle was for choropleth map presentations to use statistical data still imprecisely referred to as relative, as well as using a distribution series as a method of generalizing data.