Suitable for readers with a computer science background as well as those in geography and other disciplines where visualization techniques are used, this book presents a new model of visualization that unifies design and evaluation issues in a single framework. It splits the design issues into four areas: problem characterization, data and task abstraction, visual encoding, and interaction techniques. A broad set of techniques are analyzed through the building blocks of visualization. The book also explores the practice of visualization, including difficulties in problem-driven research.