Description

There are many frameworks and libraries that simplify the building of interactive maps in modern browsers: from low-level ones for programming data-driven visualizations. We no longer need to have maps readymade as static pictures; they just become visual output that is created on-the-fly from the underlying databases, their layout and design dependent on the user's preferences or inputs.

In his Sémiologie Graphique (1967), Bertin described the systematical encoding of data in graphical symbols, using steps that can be taken by a human, or a human using a computer. But they can't be used as such by a computer on its own, because they are not formalised. Leland Wilkinson (The Grammar of Graphics, 1999) introduced a formal grammar for creation of graphics in a way a computer can implement. We can implement visualisation pipelines using such formal grammars: ranging from low-level to high-level (expressive & detailed vs. concise & simple) and either procedural or declarative (tell the computer how to do it vs. what to achieve).

Recently, the University of Washington Interactive Data Lab created Vega-Lite, a high-level declarative grammar for data visualisation using the JSON syntax. An example of a Vega-Lite visualization pipeline is shown in Fig. 2.

In this thesis, we want you to explore the potential of formal declarative grammars such as VegaLite for the construction of automated cartographic visualisation pipelines. Your use case can be the experimental National Atlas of the Netherlands [ref2], an experimental web mapping system that consumes data from the Dutch National GeoData Infrastructure and maps these in an interactive web client. The current experiment is based on the D3 Javascript library, so conversion to a VegaLite (which runs on top of D3) based setup should be possible.

Objectives and Methodology

Explore the potential of formal declarative grammars such as VegaLite for the construction of automated cartographic visualisation pipelines

Further reading

The Vega-Lite web site: https://vega.github.io/vega-lite/ and an academic paper about it: idl.cs.washington.edu/papers/vega-lite/
About the experimental National Atlas of the Netherlands: B. Köbben. Towards a National Atlas of the Netherlands as part of the National Spatial Data Infrastructure. The Cartographic Journal, 50(3):225–231, 2013. doi: 10.1179/1743277413Y.0000000056.
The Thematic Map Tutor, a web-based visualisation pipeline demonstrating Bertin's Graphic Grammar (https://kartoweb.itc.nl/TMT/); and a paper about it: https://doi.org/10.7287/peerj.preprints.27203v1