ColorBrewer.org: An Online Tool for Selecting Colour Schemes for Maps

Abstract

Choosing effective colour schemes for thematic maps is surprisingly difficult. ColorBrewer is an online tool designed to take some of the guesswork out of this process by helping users select appropriate colour schemes for their specific mapping needs by considering: the number of data classes; the nature of their data (matched with sequential, diverging and qualitative schemes); and the end-use environment for the map (e.g., CRT, LCD, printed, projected, photocopied). ColorBrewer contains 'learn more' tutorials to help guide users, prompts them to test-drive colour schemes as both map and legend, and provides output in five colour specification systems.     

Interactivity Types in Geographic Visualization

This paper introduces and discusses types of interactivity that can be used in digital mapping environments. The interactivity types are placed in the framework of geographic visualization (GVis) in order to extend the GVis emphasis on exploratory, interactive and private functions of spatial displays. After defining interactivity in general, four categories of interactivity are proposed: with (1) the Data; (2) the Data Representation; (3) the Temporal Dimension; and (4) Contextualizing Interaction. Three benefits of this typology are discussed. First, interactivity types can be combined to build an interactive environment. More powerful interactive mapping environments not only employ more interactivity types, but combine types from different categories. Second, the typology allows cartographers to compare and critique different mapping and GIS environments and gives cartography educators and students a mechanism for understanding the different types of interactivity, as well as a set of concepts for imagining and creating new interactive environments. Third, a typology of interactivity gives interface designers a mechanism with which to identify needs and measure interface effectiveness. In order to examine these issues in practice, two common interactive mapping environments are briefly examined to determine the interactivity types employed, and a measurable difference of interactive potential is obtained.