Visualizing Terrain

This chapter considers approaches for symbolizing a particular type of smooth, continuous phenomenon—Earth&s;s terrain. Methods for depicting terrain can be divided into those that utilize a vertical (plan) view and those that utilize an oblique view. Methods for depicting a vertical view include hachures, contour-based methods, Raisz&s;s physiographic method, shaded relief, and various morphometric techniques (which focus on the structure of the terrain such as aspect and slope). Oblique methods covered include block diagrams, panoramas (or bird&s;s-eye views ), and plan oblique relief. Although oblique views have a distinctive 3-D appearance, they are still created on a 2-D surface (on either paper or a graphics display device). The chapter also covers physical models (or physicalizations) that provide a truly 3-D view (i.e., users can hold and manipulate small models in their hands). Given the common use of shaded relief for visualizing terrain, the last section of the chapter focuses on several related issues, including (1) generalizing the terrain; (2) selecting an appropriate azimuth (orientation of the sun) and sun elevation; (3) lighting model issues; (4) the representation of Swiss-style rock drawing; and (5) approaches for adding colored thematic layers to shaded relief.

Cartography · Computer graphics (images) · Geography · Remote sensing · Terrain · Computer Science · Geology · Rangeland Management and Livestock Ecology