Visualization and Query of Spatial Data

Abstract

This chapter provides an overview on visualization and query of spatial data. Visualization is a critically important function in GIS. The availability of low-cost computer graphics in the 1980s was one of the catalysts for the growth of GIS. The ability to make rapid interactive spatial queries is a valuable GIS function that complements visualization. This chapter discusses some aspects of visualization and query, and deals with the following topics: (1) the composition of cartographic images, (2) display hardware, (3) color models, (4) hardcopy plotting, (5) visualization of surfaces, (6) dynamically-linked data views, and (7) spatial query. The visualization process in GIS mainly involves generating and looking at cartographic images, which are maps in the form of digital images. Visualization also involves other views of the data present in a GIS database. Dynamically linked data views are especially powerful if they are combined with interactive spatial query, permitting objects selected in one view to be simultaneously highlighted in other views. The chapter also describes the basic process of composing a cartographic image, visually combining data about several spatial data layers, and superimposing cartographic annotation.