Where did my Lines go? Visualizing Missing Data in Parallel Coordinates

Alex Bäuerle*

Ulm University

Simon der Kinderen

Ulm University

Jimmy Johansson Westberg

Linköping University

Daniel Jönsson

Linköping University

Timo Ropinski

Ulm University

Computer Graphics Forum (Proc. of EuroVis) 2022

* authors contributed equally


We evaluate visualization concepts to represent missing values in parallel coordinates. We focus on the trade-off between the ability to perceive missing values and the concept’s impact on common tasks. For this purpose, we identified three missing value representation concepts: removing line segments where values are missing, adding a separate, horizontal axis onto which missing values are projected, and using imputed values as a replacement for missing values. For the missing values axis and imputed values concepts, we additionally add downplay and highlight variations. We performed a crowd-sourced, quantitative user study with 732 participants comparing the concepts and their variations using five real-world datasets. Based on our findings, we provide suggestions regarding which visual encoding to employ depending on the task at focus.


	title={Where did my Lines go? Visualizing Missing Data in Parallel Coordinates},
	author={B{\"a}uerle, Alex and van Onzenoodt, Christian and der Kinderen, Simon and Johansson Westberg, Jimmy and J{\"o}nsson, Daniel and Ropinski, Timo},
	journal={Computer Graphics Forum (Proc. of EuroVis (2022))},