This book is based upon the extensive practical experience of the authors in designing and developing software tools for visualisation of spatially referenced data and applying them in various problem domains. These tools include methods for cartographic visualisation; non-spatial graphs; devices for querying, search, and classification; and computer-enhanced visual techniques. A common feature of all the tools is their high user interactivity, which is essential for exploratory data analysis. The tools can be used conveniently in various combinations; their cooperative functioning is enabled by manifold coordination mechanisms.