This unit presents an overview of concepts related to cartographic visualization. It begins with some notes on cartography, including motivation, user considerations, and components of a visualization system. Graphic variables including location, value, hue, size, shape, spacing and orientation are described, and limitations—imposed by hardware and human perceptual and cognitive abilities—are discussed. Visualization of the temporal dimension and three-dimensional data are briefly discussed.

This unit considers one of the most important technical issues in GIS—data accuracy. It examines several aspects of data accuracy included in the National Standard for Digital Cartographic Data: positional accuracy, attribute accuracy, logical consistency, completeness and lineage.