Data transformations in Vega

• Thesis title in Czech: Transformace dat v prostředí Vega
• Thesis title in English: Data transformations in Vega
• Key words: vega|vizualizace dat|formální sémantika
• English key words: vega|data visualization|formal semantics
• Academic year of topic announcement: 2024/2025
• Thesis type: Bachelor's thesis
• Thesis language: angličtina
• Department: Department of Distributed and Dependable Systems (32-KDSS)
• Supervisor: Mgr. Tomáš Petříček, Ph.D.
• Author: hidden - assigned and confirmed by the Study Dept.
• Date of registration: 15.11.2024
• Date of assignment: 15.11.2024
• Confirmed by Study dept. on: 25.11.2024
• Date and time of defence: 19.06.2025 09:00
• Date of electronic submission: 07.05.2025
• Date of submission of printed version: 07.05.2025
• Date of proceeded defence: 19.06.2025
• Opponents: Mgr. Jiří Beneš

Guidelines

The Vega library [1,2,3] is a widely-used system for creating interactive data visualizations. Unfortunately, Vega can be hard to use and a small change in the Vega specification can result in an error or an invalid output. One class of errors arises from Vega data transformations, which can be used to reshape the input data prior to visualization. If the parameters of Vega data transformations are invalid or missing, Vega may report an error or silently continue with incomplete data.

The aim of this thesis is to understand and document the behavior of Vega data transformations and use this insight as the basis for a tool capable of checking a range of possible error conditions in the specification of Vega data transformations. The thesis should describe the evaluation of Vega data transformations using a small formal semantics, use the formal semantics to specify error conditions and implement a prototype tool that will ensure that data transformations included in Vega specifications are free of such errors. The formal semantics should capture the minimal "essence" of Vega in the sense of, e.g. [5] and may use graph-based model of evaluation as in [4].

References

[1] Vega Project and contributors. "Vega – A Visualization Grammar" Online at: https://vega.github.io/vega/ (Retrieved 5 Nov 2024)
[2] Satyanarayan, Arvind, et al. "Vega-lite: A grammar of interactive graphics." IEEE transactions on visualization and computer graphics 23.1 (2016): 341-350.
[3] Satyanarayan, Arvind, et al. "Reactive vega: A streaming dataflow architecture for declarative interactive visualization." IEEE transactions on visualization and computer graphics 22.1 (2015): 659-668.
[4] Petricek, Tomas. "Foundations of a live data exploration environment." The Art, Science, and Engineering of Programming, 2020, Vol. 4, Issue 3, Article 8 (2020)
[5] Madsen, Magnus, Ondrej Lhotak, and Frank Tip. "A Semantics for the Essence of React." European Conference on Object-Oriented Programming. 2020.