Understanding and applying these taxonomies is crucial for translating a domain problem into a visualization design. They provide a common language and a systematic approach to task abstraction.

Brehmer and Munzner’s Typology (2013)

This taxonomy provides a high-level, human-centered view of visualization tasks. It categorizes tasks into three top-level goals:

  1. What does the user know?
    • Lookup: Find a known item in a known location.
    • Browse: Look for an item without a specific target.
    • Locate: Find a known item in an unknown location.
    • Explore: Look for any unknown items or patterns.
  2. Why does the user perform the task?
    • Enjoy: For entertainment or aesthetic pleasure.
    • Find Anomalies: To spot unexpected patterns.
    • Synthesize: To combine information from different sources.
    • Analyze: To draw conclusions and gain insights.
  3. How does the user interact?
    • Annotate: Add notes or labels.
    • Share: Export or distribute.
    • Present: Create a presentation from a view.

For our bus delay case study, we focus on Explore (for finding unknown patterns) and Analyze (for drawing conclusions about delay causes).

Amar, Eagan, and Stasko’s Low-Level Task Taxonomy (2005)

This taxonomy provides a more granular, operational view of tasks that a visualization tool must support. It describes specific user actions.

  1. Retrieve Value: Find the value of a specific data point.
  2. Filter: Find data points that meet a condition.
  3. Find Extremum: Find the maximum or minimum value.
  4. Sort: Order data points based on a specific value.
  5. Determine Range: Find the range of values in a dataset.
  6. Characterize Distribution: Describe the overall shape of the data.
  7. Find Anomalies: Identify outliers.
  8. Cluster: Find groups of similar data points.
  9. Correlate: Find relationships between different data variables.

For our bus delay case study, we use these to specify our low-level tasks, as seen in the task abstraction log (e.g., Filter by day of the week, Correlate weather with delays).