Mapping Hacks

254

|

Chapter 5, Mapping with Gadgets

#57 Connect to Your GPS from Multiple Applications

HACK

HACK

#57

Connect to Your GPS from Multiple

Applications Hack #57

In Linux, BSD, and OS X, you can get live GPS data across different

processes—and even different computers—simultaneously.

While almost miraculous in their basic operation, your average GPS receiver

lacks much in the way of wits all on its own. Even the fanciest of them can

do little more than plot your location on a map, and maybe give directions

to a destination. Once combined with a computer, though, that same GPS

receiver can power a wide range of new and different applications, from

auto navigation systems like gpsdrive

[Hack #63] to network sensing tools like

Kismet and Macstumbler

[Hack #17]. However, the very nature of the serial

connection linking the two—be it RS-232, USB, or Bluetooth—limits the

GPS to talking to one application at a time. As soon as you want to do more

than one thing at a time with the data you’re getting from that GPS receiver,

you will find yourself in a world of sadness and regret.

Fortunately, there is a way around this tragic outcome! For salvation, you

can turn to gpsd, a GPS data multiplexer, which runs as a daemon on *NIX

operating systems, including OS X. gpsd handles the nitty-gritty details of

listening to the GPS receiver and then rebroadcasts the information it

receives to other applications over a TCP/IP