The use of maps in the exploration of geographic data

Abstract

This dissertation is about map use research in exploratory cartography. Exploratory cartography is a cognitive process in which maps are used as tools for discovery, to solve the problem of gaining insight into unknown geographic relationships. In the past, users had to rely fully on the static maps prepared for them by others. Nowadays, with the widespread availability of geographic data, computers and cartographic visualization software tools, users are able to generate and adjust, just for themselves, the map displays they require. Indeed, cartography now has the potential to be fully "demand-driven" instead of "supply-driven".

To improve the functioning of maps, map use research has been executed since the 1950s. But research has been limited to the functioning of an individual, static or interactive map display on its own. What has been lacking is research in which not only the functioning of a given map is investigated, but also the complete process of finding, selecting, retrieving, adjusting or generating map displays. This is one of the first attempts to obtain more information about these "pre-map-use" stages in exploratory cartography. To investigate the selection and use of maps in the process of exploring geographic data, a case study was defined in which users could make use of a great variety of map types in visualizing a broad spectrum of geographic data. It encompassed a case in regional exploratory studies, one of the first stages in geographic research in which geographers try to gain insight into the geography of a region unknown to them. Such geographers were chosen as test persons and the region selected was Overijssel. The test persons were asked to construct a schematic graphic model of the geography of this region, derived from the concept of chorèmes and based on the use of maps that they selected or generated themselves. Use was made of a combination of qualitative research techniques centred round the think aloud method in an experiment room with a unique combination of hard- and software. The resulting verbal and action protocols were analysed on the basis of a hypothetic model of geographic problem-solving, derived from the analysis of the task in hand and from cartographic and (regional) geographic theory. Study of the outcomes resulted into the conclusion that exploratory cartography is not as interactive, private or demand-driven as is often assumed, at least not when it comes to regional exploratory studies. Here, the use of maps still is very much of a supply-driven nature. Users - experts and novices alike - prefer to start their geographic data exploration with ready-made maps that are immediately available. They even prefer maps on paper and possibly combined into an atlas. Such maps are not selected on the basis of clear geographic questions. If users have a demand at all, and do not just browse through what is immediately available to them, the geographic theme is a more important selection criterion - no matter how that theme is actually represented. In the early stages of regional exploratory studies, users do not want to generate their own map displays, nor do they want to adjust existing ones or interact with them. The main reason behind the supply-driven nature of map use is the time factor. Therefore, and in view of the application potential of highly interactive cartographic visualization software tools, what was called exploratory cartography may better be called analytic cartography, for application in a later stage in regional studies in which hypotheses about the main geographic characteristics have already been formulated, but need to be analysed further.