A chorem-based approach for visually synthesizing complex phenomena

When dealing with scenarios referring to complex issues, such as political, economic and demographic problems, the usage of visual metaphors represents a more effective approach in supporting users to locate facts and new patterns. In this paper, we describe a research project whose aim is to investigate a cartographic solution able to represent dynamics, movements and changes that underlie possible problems. The solution we propose is based on the chorem concept. It represents an immediate synthesis of data of interest, and provides expert users with both a global view of objects and phenomena, and an insight into a specific issue. Based on preliminaries studies, we first provide a formal definition and classification of chorems in terms of structure and meaning, meant to homogenize chorem construction and usage. Then, a system to generate chorematic maps from available data sets is described and an XML-like language, named ChorML is specified, enabling system modules communication. In order to validate our approach, we exemplify the construction of a chorematic map, which depicts the most significant flows of migrating population in Italy in 2000. Such a synthesis may represent the starting point for further processing tasks aimed to derive spatial analysis data, as well as to support expert users in decision making.