The Ubiquitous Augmented Reality (UAR) system (Xinyu, 2009) combines mobile AR with ARToolkit1 to enable the visualization of indoor environmental sensor data. Upon viewing a tracking marker, data from a sensor also located at the marker’s position is overlaid on top of the marker, indicating the sensor’s real time status. Similarly, Goldsmith et al. (2008) also present SensAR, an ARToolkit visual tracking system to overlay sensor values in real time. The simple use of metaphors in visualization representations enables intuitive understanding of data, such as the use of thermometer representations for temperature (Figure 4).
