EXPLOREMAP: An Exploration System for Choropleth Maps

Abstract

Software for interactive choropleth mapping typically focuses on design, with the assumption that the resulting map will be used like a traditional paper one. We believe that interactive graphics also should enable users to explore the database underlying a map. In this vein, we have developed software that will permit users to both design a map and explore the underlying database.

The exploration component, the raison d'être for the software, includes the following options: Overview, Areas, Reclass, Regions, Tables, and Graphs & Stats. Within Overview, users can display map elements in sequence, any combination of classes, and highlighted subsets of the data. Within Areas, users can determine values associated with areas, compare values for two areas, and determine minimum and maximum values for classes and the entire map. Reclass allows users to reclassify the map data temporarily, thus determining the effect of different classification schemes. The Regions option permits regions to comprise specified areas, while Tables and Graphs & Stats present tabular, graphical, and statistical displays of the data in pop-up windows.

The user interface consists of pull-down menus and mouse input, and the software is compatible with standard IBM VGA graphics hardware. Some potential future enhancements include the display of 256 colors at one time, which will speed display and permit animation; other symbol approaches such as three-D; and links with GIS.

Key Words:

• Key Words
• map exploration
• choropleth maps
• interactive graphics
• cartography