As geographic information increasingly plays a key role in local government services and processes, its online presence has expanded. Due to the complex nature of geographic information and its representation, mapping applications may require special consideration by developers. Usability concerns the ease of use and learnability of those online applications. Standard usability practises may be too general for the evaluation of different technologies.

This paper presents a set of five web mapping heuristics. These heuristics are likely to be of interest to both novice and experienced web mapping developers as well as those interested in identifying key trends in the presentation of geographic information. We propose five heuristics (findability, cartography, functionality, user experience and performance) to evaluate the usability of online maps. The heuristics are then applied to the current online provision of geographic information in the South Island New Zealand to illustrate their use.