According to Wikipedia, desire lines (or social trails) are the trails which manifest on the surface if people heading for a certain destination take a shortcut through the grass. This great post further explains the concept of desire lines, and discusses why landscape architects should take this human behavior into account before planning pathways. The map of the Michigan State University shows an example were architects waited until desire lines emerged and paved them afterwards.

Sometimes we GIScientists struggle with the phenomenon of the rise of geospatial applications in the web (i.e. Google Maps, OpenStreetMaps, Flickr, ...). In the past we were told that research is targeting the theoretical foundations of GIScience, and that the stuff we develop is years ahead of the products available on the market. But the web, Virtual Globes, or the abundance of GPS devices changed everything. This all developed so fast that we have a hard time to catch up. In fact, all we can do is to react and try to understand what's going on.

I like the analogy of desire lines and the ongoing social phenomena of the web. In the past we were the architects who decided how people interact with the concept of space, today we need to study the human behaviour in the web and study the emerging desire lines. And once we know what the people care about we can try to pave the ways and provide the theoretical foundations for the geospatial web.

The working group of Prof. Krüger here at ifgi has a great demo movie for their technology for mobile map interaction. The basic idea is to use a mobile device with a camera which scans a classic paper map. On the display of the device, additional information is then projected on this scanned image, such as personally tagged locations. For further information, please refer to this abstract or the paper The Maurauders Lens.