QLandkarte GT is the ultimate outdoor aficionado's tool. It supports GPS maps in GeoTiff format as well as Garmin's img vector map format. Additionally, it is the PC-side front end to QLandkarte M (see next), a moving map application for mobile devices.
There are many ways of writing coordinates, and converting between the different ways is non-obvious but also quite trivial.
KisMap is a collaborative directory of wireless networks. It collects log files made with Kismet, a wireless network detector for linux.
Hamburg ist eine der Geocaching Hochburgen Deutschlands. Innerhalb der Stadtgrenzen gibt es 841 aktive Geocaches (22.01.2008).