Bertin was Right: An Empirical Evaluation of Indexing to Compare Multivariate Time-Series Data Using Line Plots |
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| Authors | Wolfgang Aigner1, 2 Christian Kainz2 Rui Ma2 Silvia Miksch1, 2 1Department of Information and Knowledge Engineering (ike), Danube University Krems, Austria 2Institute of Software Technology and Interactive Systems, Vienna University of Technology, Austria |
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| Abstract | Line plots are very well suited for
visually representing time series. However, several difficulties arise
when multivariate heterogeneous time-series data is displayed and
compared visually. Especially, if the developments and trends of
time-series of different units or value ranges need to be compared, a
straight forward overlay could be visually misleading. To mitigate
this, visualization pioneer Jacques Bertin presented a method called
indexing that transforms data into comparable units for visual
representation. In this paper, we want to provide empirical evidence
for this method and present a comparative study of the three visual
comparison methods linear scale with juxtaposition, log scale with
superimposition, and indexing. While for task completion times,
indexing only shows slight advantages, the results support the
assumption that the indexing method enables the user to perform
comparison tasks with a significantly lower error rate. Furthermore, a
post-test questionnaire showed that the majority of the participants
favor the indexing method over the two other comparison methods. |
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| Downloads |
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| Images | To retrieve an enlarged version of the images,
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Prototype application showing an indexed line chart with two stocks |
 Evaluation mode for automated testing |
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