User Interface Design Considerations for a Time-Space GIS

This presentation summarizes the user requirements for analysis and visualization of hydrologic time series data in a GIS. Several designs for cartographically presenting time series data points and organizing the user interface have been tested by hydrology students with varying levels of GIS experience. Usability was evaluated using a survey where participants worked on the task of calculating total precipitation and calculating runoff coefficient of a watershed in the users‘ area of interest. Completing the tasks in the survey required filtering, overlay, interpolation or aggregation operations across the time and the space dimensions. The preliminary results of the survey including user comments are presented. Results of the usability studies are guiding the developer team in improving the user interface design of HydroDesktop, an open source GIS application specially designed for interactive visualization and analysis of geographic and time series information. Features of HydroDesktop include spatial and temporal filtering and interpolation, simultaneous display of map and graph view, and linking of spatial features to time-aggregated observation data values. By focusing on usability, we envision HydroDesktop to become an invaluable software tool for exploring the spatial and temporal interaction of hydrologic processes.