Visualising Structured Data on Geographic Maps: Evaluating a Hexagonal Map Visualisation
January 30, 2012 Comments Off on Visualising Structured Data on Geographic Maps: Evaluating a Hexagonal Map Visualisation
An important aspect of spatial analysis is the choice of appropriate forms of representation. Choropleth maps are an appropriate, widely-used representation for univariate spatial data sets; but how can data distributions be visualised on geographic maps? I.e., how can one visualise data that has spatial, categorical, and quantitative aspects?
We developed a map-based histogram based on a hexagonal tessellation scheme and will evaluate it with geometric and spatial analysis techniques. Such visualisations can be used to illustrate e.g. cultural differences, as demonstrated here with a data set on language-specific colour naming preferences. Exemplary questions of this data may be: what are the most popular colour categories within a country? How fine or broad are the colour categories for particular hues? Do Spanish-speaking respondents have more fine-grained colour name categories for orange tones than English-speaking ones?
In developing such a visualisation there are a number of challenges to overcome which we will outline below. A fundamental question is whether we can illustrate spatial, categorical, and quantitative aspects (country association, colour names, and colour frequencies) without introducing needless visual clutter. In Edward Tufte’s terms: we will strive for a high data-ink ratio.
Get the report: Hexagonal Maps 2011-12-16