What is Halos

Due to advances in hardware technologies, mobile devices are increasingly capable of handling largescale data sets. While this development broadens the application scope of smartphones and PDAs, it also means that high information loads must be displayed on very limited screen real estate. A solution to this problem may be provided by starfield displays. Starfield displays maximize the data-pixel ratio by presenting data inside a zoomable 2-D scatterplot. However, a drawback is that once users have zoomed into the information space, they tend to become lost, due to the clipping of orientation cues. The chapter summarizes the research results of recent projects that were conducted to improve the navigation and orientation features of starfield displays on small screens. Several approaches, such as smooth zooming, overview window, and fisheye view, have been implemented and user-tested. The results may support interface designers when targeting mobile devices.