Hardware Reference
In-Depth Information
Setting up a GPS waypoint logger
When you can't travel with your Pi and you can't be within the Wi-Fi range to
monitor its position in real time, you can still see where it has been by recording
and analyzing
GPX iles
—a standard file format for recording GPS waypoints,
tracks, and routes. Use the following command to start logging:
pi@raspberrypi ~ $ gpxlogger -d -f /tmp/gpslog.gpx
The
-d
argument tells
gpxlogger
to run in the background and the
-f
argument
specifies the logfile. Before you open up the log file in Google Earth, it's important
that the
gpxlogger
process has quit properly, otherwise you might end up with a
broken log (usually this can be fixed by adding a closing
</gpx>
tag to the end of the
file). Kill the process using the following command:
pi@raspberrypi ~ $ killall gpxlogger
Next, start the simple Python HTTP server:
pi@raspberrypi ~ $ cd /tmp && python -m SimpleHTTPServer
Then download the log file to your computer through the following address:
http://[IP address]:8000/gpslog.gpx
Now in Google Earth, under the
File
drop-down menu, select
Open…
and point
to your log file. Click on
OK
in the
GPS Data Import
dialog that follows, and you
should see a post for your GPS device under
Temporary Places
in the sidebar to the
left and time controls that can be used to play back the travel route.
Mapping GPS data from Kismet
If you run Kismet, which was discussed in the
Monitoring Wi-Fi airspace with Kismet
section of
Chapter 4
,
Wi-Fi Pranks - Exploring Your Network
, with GPS support, it will
record geographic information about the access points to
~/kismetlogs/Kismet-
[date].netxml
. To massage this data into the KML format that Google Earth
expects, we need to install an additional utility called
GISKismet
.
1. It's written in Perl and requires a couple of modules to be installed first:
pi@raspberrypi ~ $ sudo apt-get install libxml-libxml-perl libdbi-
perl libdbd-sqlite3-perl
2.
Now we need to download and install the GISKismet utility itself, with the
following command sequence:
pi@raspberrypi ~ $ wget http://www.intestinate.com/giskismet-
svn30.tar.bz2
pi@raspberrypi ~ $ tar xvf giskismet-svn30.tar.bz2
