Interactive Visualization - Human Control of Visualization

Human Control of Visualization

The Programmer's Hierarchical Interactive Graphics System (PHIGS) was one of the first programmatic efforts at interactive visualization and provided an enumeration of the types of input humans provide. People can:

1. Pick some part of an existing visual representation;
2. Locate a point of interest (which may not have an existing representation);
3. Stroke a path;
4. Choose an option from a list of options;
5. Valuate by inputting a number; and
6. Write by inputting text.

All of these actions require a physical device. Input devices range from the common – keyboards, mice, graphics tablets, trackballs, and touchpads – to the esoteric – wired gloves, boom arms, and even omnidirectional treadmills.

These input actions can be used to control both the information being represented or the way that the information is presented. When the information being presented is altered, the visualization is usually part of a feedback loop. For example, consider an aircraft avionics system where the pilot inputs roll, pitch, and yaw and the visualization system provides a rendering of the aircraft's new attitude. Another example would be a scientist who changes a simulation while it is running in response to a visualization (see Visulation) of its current progress. This is called computational steering.

More frequently, the representation of the information is changed rather than the information itself (see Visualization (graphic)).