Choropleth maps and diagram maps in atlas of cartographic presentation methods

Abstract

The online Atlas kartograficznych metod prezentacji [Atlas of cartographic presentation methods, hereinafter the Atlas] is a research project being carried out at the Department of Cartography of the University of Warsaw. The reason for such a publication was the rapidly growing popularity of GIS systems which allow nearly every user to make a map easily and quickly. The aim of the project is to systematise and disseminate knowledge about the use of cartographic presentation methods, including their classification and the formalisation of selected quantitative methods. Formalisation 1 is understood as a process of translating a set of data into a cartographic language and is an attempt at defining the principles and conditions of a proper cartographic presentation, since the clearly formulated assumptions underpinning the individual methods of cartographic presentation would allow almost everyone to draw maps correctly. In 1 formalisation [Latin: formalis 'referring to shape, form'], log. procedure intended to translate the content of one theory (system) from a natural, non-formalised language into a formalised one, e.g. that of logic (www.encyklopedia.pwn.pl) the project, we did not use any of the available GIS software in an attempt to discuss all stages of map-making step-by-step, in a way that helps to understand the very nature of cartographic presentation. The Atlas consists of three parts. The first includes papers on the history and theoretical foundations of cartographic presentation methods. The second discusses the step-by-step procedure showing how a thematic map should be elaborated. An important aspect of this part is a brief description of five forms of presentation, commonly known as cartographic methods. Knowledge of the attributes of each of these forms is a precondition for good map making. The third part offers several dozen examples of adding content to the pattern described in part two. In effect, maps are developed in a way that allows for their modification in order to obtain new (and correct) variants of the basic map. This study discusses selected issues related to two of the five presentation methods analysed in the project, viz. the choropleth map and the diagram map.