Scatterplots and scenes: visualisation techniques for exploratory spatial analysis

Abstract

A collection of geographic data from a particular region contains many explicit and implicit relationships which are difficult to display and communicate without resorting to statistical summarisation or fragmentation into themes. This paper addresses the problems of exploring interconnections between layers of data using state-of-the-art visualisation techniques and is based on the premise that visual exploratory data analysis is a useful tool for providing insight into the complex and subtle relationships that occur in geography. The tools and techniques described extend beyond the current capacity of commercial geographic information systems in terms of (a) the flexibility of the scene description, (b) the volume of data (particularly the number of distinct layers or themes that are viewable concurrently) and (c) the facilities by which the user may study relationships. The techniques proposed are justified from a psychometric standpoint and some important limitations with their use are described. As well as the pictures shown in the paper, further results are given in the form of high resolution colour images, VRML scenes and video clips which may be downloaded from an accompanying Web site.