A graphic with two parts. Part A illustrates an accessible visualization structure in the form of a tree for an example scatterplot. The tree structure is comprised of encoding and data entities, including the following: the Chart Root (i.e., a summary textual description of the chart), Encodings (i.e., the chart's x-axis, y-axis, legend, x-y grid), Intervals/Categories (i.e, navigating by selecting axis intervals or data categories), and individual Data Points. Navigating between these different entities is accomplished by up, down, left, right key presses. Part B illustrates three different ways of navigating a visualization structure: Structural navigation (i.e., following the tree structure described above), Spatial navigation (i.e., exploring up, down, left, right within the x-y grid of the chart), and Targeted navigation (i.e., navigating in a more particular fashion via drop-down menus).