Assessing cartographic products for visual usability

Abstract

In societies in developed nations the simple fact is that many Web information graphics users will be colour-blind. Around 0.4 % of Caucasian females and 10 % of Caucasian males are considered to be colour-blind. Colour-blind users will see some map data differently from users who are normally sighted. Therefore design strategies need to be developed that ensures that thematic map information is transferred effectively. For maps to be usable, they first must be designed to accord to certain criteria. The criterions are many, and they range from elements that can be tested subjectively and objectively. This paper provides background information and the results of a project undertaken to evaluate the effectiveness, from a usability perspective related to colour-blindness, of a suite of maps published on the Web. They range from topographic and thematic maps produced entirely in-house to maps published as mash-ups. Maps were evaluated for colour-blind users.