Tag Archives: map

What’s in the off-screen? Different techniques to show POIs on a map

My student Sascha and I implemented some visualization techniques for maps on phones. Don’t know what this is all about? Let’s have a look at the abstract of the paper Halo: a technique for visualizing off-screen objects:

As users pan and zoom, display content can disappear into off-screen space, particularly on small-screen devices. The clipping of locations, such as relevant places on a map, can make spatial cognition tasks harder. Halo is a visualization technique that supports spatial cognition by showing users the location of off-screen objects. Halo accomplishes this by surrounding off-screen objects with rings that are just large enough to reach into the border region of the display window. From the portion of the ring that is visible on-screen, users can infer the off-screen location of the object at the center of the ring. We report the results of a user study comparing Halo with an arrow-based visualization technique with respect to four types of map-based route planning tasks. When using the Halo interface, users completed tasks 16-33% faster, while there were no significant differences in error rate for three out of four tasks in our study.

A couple of other approaches try to support similar tasks. We thought testing is better than believing and implemented three different visualization techniques for digital maps on Android. There is a demo app in the market (direct link). We tried to make the whole thing portable but only tested on the G1 and the emulator. I would love to know if it works on other devices like the Motorola Milestone

I removed the app from the market because I lost my keystore and can’t update it anymore. If you are interested in testing it check out the Map Explorer. It is an updated version that you can find in the market.