Annotated atlas maps to support ‘Comparison’

Atlases are used when interested in finding locations or regions, and in comparing spatio-temporal patterns. Geographic reference atlases support this from a more generic perspective, while school and thematic atlases do so with specific objectives in mind.

This contribution concentrated on the atlas strength of comparing regions using thematic maps. In such comparison, like “what is the difference in population density between region A and region B?” usually location (e.g. regions’ locations and physical settings), attribute (e.g. geographic units), and time (e.g. age) play a role. Executing this comparison task is in itself difficult enough. How can the atlas support these tasks better than by just offering the right maps?

The keyword is annotation. Annotations in maps are not new and have been used to highlight extremes, replace legends, among others. In this atlas support solution, annotations are suggested at three levels. First - the cartography level - to explain the map type (Do map readers really understand for instance a choropleth or flow map? Do they understand the methodology/data processing behind the map type?). Second - the geography level - to explain the mapped phenomena (Do they see the spatio-temporal patterns? Do they see the outliers and extremes?), and third - the knowledge level - to explain comparison options (Do they known how to use an atlas to compare regions over space, attribute and time?). The paper will discuss how these different types of annotations can look like, and when they should be visible in the atlas environment