The Argumentation Map (Argumap) concept was proposed by Rinner (1999, 2001) to support planning processes by facilitating distributed, asynchronous discussions. Argumaps are based on the combination of an online discussion forum and an online geographic information system (GIS) component. Argumaps were conceived as a method to formalize debates that have geospatial elements in the discussion. Because of their distributed nature, Argumaps benefit from a number of characteristics of the Internet, for example the ability to share information with many stakeholders (Laurini 2004) and the anonymity provided in online discussions (Kingston et al. 1999).
Kessler (2004) implemented an Argumentation Map prototype as a proof of concept. This Web-based prototype integrates a discussion forum and a simple mapping tool. Technology used in the implementation includes the GeoTools Lite mapping tool kit, a custom-built Java applet for the discussion forum, the MySQL database for storage of geographically referenced discussion contributions, and the University of Minnesota MapServer for the supply of background map layers. Kessler chose these open-source software tools on the grounds that they fulfilled the requirements for the Argumap concept set out by Rinner (1999) and that they minimized development costs.
The functionality of the prototype includes map navigation (zoom in/out, pan, zoom to full extent), layer management (switching layers on and off), and display of map labels (e.g., building names). In the discussion forum, contributions are displayed by their subjects, authors, and dates in lists with indentations by discussion threads, and the body of a selected contribution is displayed in a text window. When a contribution is selected in the forum, its geographic references will be highlighted on the map. Likewise, when a map object is selected, all discussion contributions referring to this object will be highlighted in the forum. The Argumap prototype also provides a full-text search tool for the discussion forum and summary statistics when browsing the map (number of contributions per map object). Finally, in terms of participation in georeferenced debates, the tool offers a log-in feature that enables the user to start a new discussion thread or respond to existing contributions. When editing a message, a set of geographic references can be specified in the map and is stored together with the text of the message. The functionality and architecture of the prototype is summarized in further detail by Kessler et al. (2005).
The stakeholders in planning processes usually are heterogeneous groups with a variety of knowledge and skill levels (Healey 1997, Simao and Densham 2004). Because of the wide range of possible users, any planning support system must be designed in such a way that all are able to learn to use the majority of its functions. This introduces a motivation for a usability analysis for the Argumap prototype.
This paper provides a framework for usability analysis for participatory spatial decision support tools such as Argumaps and describes a case study. We investigated how Kessler's (2004) prototype was understood and used by a heterogeneous participant population. The following sections describe the research background, methodology, as well as the preparation and results of the case study. Conclusions are then drawn in the form of recommendations for improving the Argumap prototype. While these recommendations are specific to the software tool being analyzed, this research also provides an example for conducting usability analyses for participatory GIS tools in general.
APPROACHES TO SOFTWARE USABILITY ANALYSIS
"Human-Computer Interaction (HCI) is concerned with the design of computer systems that are safe, efficient, easy and enjoyable to use as well as functional" (Preece 1993, 11). As long as there have been computers, their developers have been concerned with how the machine and its software will be used. …