Chapter 17 - Interactive Approaches to Contouring and Isosurfacing for Geovisualization

Abstract

This chapter describes ways in which contouring and isosurfacing techniques for 3D computer graphics have evolved. In particular, it shows the way they are strongly intertwined and the way they have moved from being non-interactive to interactive processes, making them appropriate for the kinds of dynamic representation required for geovisualization. Traditionally, both contouring and isosurfacing have been seen as non-interactive processes in an interactive environment to support visualization in its broadest sense and geovisualization in particular. In the early days of contouring, packages such as SYMAP would generate detailed maps that were plotted on paper for subsequent, off-line examination. Today, contouring remains a useful technique, but the style of working has changed and the techniques that can perform are required. The evolution of contouring and isosurfacing has taken the users from initial approaches, which aimed to satisfy a passive style of computing, where the graphic depiction is used as a presentation medium, to the modern era where interactivity allows the opportunity to explore the data to gain a deeper insight through visualization. The improvements to the methods have been achieved as a result of a clearer definition of a model underlying the data—that is, a model of the entity from which it is supposed that the data has been sampled.