  Gantt charts are a widely-used idiom for visualizing temporal discrete event
sequence data where dependencies exist between events. They are popular in
domains such as manufacturing and computing for their intuitive layout of such
data. However, these domains frequently generate data at scales which tax both
the visual representation and the ability to render it at interactive speeds.
To aid visualization developers who use Gantt charts in these situations, we
develop a task taxonomy of low level visualization tasks supported by Gantt
charts and connect them to the data queries needed to support them. Our
taxonomy is derived through a literature survey of visualizations using Gantt
charts over the past 30 years.
