From Gian Paolo Saliola:
OkMap is an interactive software which allows you to work on your computer screen with digital maps that you have either bought or scanned. OkMap can also import vectorial data from the most common formats and DEM data relevant to height information. Data collected by your GPS can be downloaded on your computer, stored and displayed on the maps. They can also be used to create different types of statistics. By connecting a GPS to your laptop, you can plot your position on maps in real-time. If you are connected to the network you can constantly send your position to a remote computer, or receive the position of your companions on your computer and display the related tracks on maps in real time.