Haptic visualization of bathymetric data

Visualization of water depth in geographical maps is limited by contour line density and by human ability to distinguish a subtle difference of the color gradient at a specific map scale. We were interested in whether it is it possible to increase the accuracy of subjective assessment of the bathymetric information coded by color intensity when visual observation would be complemented with haptic feedback presented as a function of the water depth. This paper describes the results of an evaluation of the new interaction technique that has potential to increase the estimation accuracy of color-coded information presented in a two-dimensional space of a topographic map. In particular, it was demonstrated that untrained subjects could accurately navigate between two geographic locations on the map of the lake by providing the necessary depth when values of the color intensity were associated with haptic feedback presented as a function of the lake floor. A comparative evaluation of the accuracy of navigation was carried out visually, using a regular mouse, and instrumentally with the StickGrip haptic device. The accuracy of navigation with the StickGrip haptic device appears to be higher by 14.25% to 23.5% in a range of bathymetric data of 40-140 m. We confirmed that a kinesthetic sense of distance to the surface of interaction (tablet) and self-perception of the finger joint-angle positions enhance the accuracy in distinguishing the color intensity of the digital map. The new mobile technique can be used as an alternative to the earlier non-mobile force-feedback devices for interaction with geospatial data.