Revised Graphics Model

A final area of major change will be in the graphics system. Some of the changes will be simple in concept. These include adding hierarchical menus, hierarchical and nested window structures, geometry management, and support for using native widgets.

At a higher level, there is a need to redesign the basic model for statistical graphs. The current model represented a compromise of expressiveness and performance. Performance is still an issue but for different reasons than five years ago. Design changes need to take account of the fact that techniques may now be applied to data sets ranging in size up to hundreds of thousands of observations.

The primary reason for a need to redesign the graphical model is best illustrated by an example. The plot in Figure 1 can be enhanced by adding a smooth through the highlighted points in the scatter plot as shown in Figure 5.

  

Figure 5: Plot linking enhanced by a smoother.

This is a simple and useful idea that could in principle be made available as an option for any plot. But there are many similar enhancements that could be made available, and doing so would create an unmanageable collection of options. A better approach is to provide a flexible set of primitive operations that allows an analyst to assemble this form of enhancement with a few operations taking a few seconds. Currently it is possible to add this enhancement with about a page of code taking an experienced user about an hour to write. This is adequate for a researcher in dynamic graphical methods to try out a new idea, but it is prohibitive for an analyst exploring a data set.

By collecting and analyzing a number of similar examples where enhancements should be possible with a few simple operations it is hoped that it will be possible to identify an effective set of primitives and a graphical model to support them.