Combining 3-D geovisualization with force feedback driven user interaction

We describe a prototype software system for investigating novel human-computer interaction techniques for 3-D geospatial data. This system, M4-Geo (Multi-Modal Mesh Manipulation of Geospatial data), aims to provide a more intuitive interface for directly manipulating 3-D surface data, such as digital terrain models (DTM). The M4-Geo system takes place within a 3-D environment and uses a Phantom haptic force feedback device to enhance 3-D computer graphics with touch-based interactions. The Phantom uses a 3-D force feedback stylus, which acts as a virtual "finger tip" that allows the user to feel the shape (morphology) of the terrain's surface in great detail. In addition, it acts as a touch sensitive tool for different GIS tasks, such as digitizing (draping) of lines and polygons directly onto a 3-D surface and directly deforming surfaces (by pushing or pulling the stylus in or out). The user may adjust the properties of the surface deformation (e.g., soft or hard) locally by painting it with a special "material color." The overlap of visual and force representation of 3-D data aides hand-eye coordination for these tasks and helps the user to perceive the 3-D spatial data in a more holistic, multi-sensory way. The use of such a 3-D force feedback device for direct interaction may thus provide more intuitive and efficient alternatives to the mouse and keyboards driven interactions common today, in particular in areas related to digital landscape design, surface hydrology and geotechnical engineering.