gps3d is a small application that displays a texture-mapped
    earth and lets you interactively explore it in 3D. It can
    also connect to a GPS unit and display in 3D all the info
    produced by the unit.

    gps3d is also capable of downloading map data from the internet
    and locally map it onto the 3D sphere interactively.

    Finally, gps3d incorporates a bunch of command line tool that
    let you interact with your GPS device and allow you to broadcast
    the info produced on the internet.