Investigating Direct Manipulation of Graphical Encodings as a Method for User Interaction
This work addresses a problem for visualization tool designers by providing incremental insights into user interaction methods.
The paper tackled the lack of empirical guidelines for how users convey intended operations through direct manipulation of graphical encodings in visualizations, by conducting a qualitative study that identified strategies, observed commonalities, and derived implications for designers.
We investigate direct manipulation of graphical encodings as a method for interacting with visualizations. There is an increasing interest in developing visualization tools that enable users to perform operations by directly manipulating graphical encodings rather than external widgets such as checkboxes and sliders. Designers of such tools must decide which direct manipulation operations should be supported, and identify how each operation can be invoked. However, we lack empirical guidelines for how people convey their intended operations using direct manipulation of graphical encodings. We address this issue by conducting a qualitative study that examines how participants perform 15 operations using direct manipulation of standard graphical encodings. From this study, we 1) identify a list of strategies people employ to perform each operation, 2) observe commonalities in strategies across operations, and 3) derive implications to help designers leverage direct manipulation of graphical encoding as a method for user interaction.