TZGPS - a GPS Applet for PalmOS

GPS is the Global Positioning System, which is a satellite-based system for accurately determining your location on the earth's surface. These days, GPS receivers have become cheap and commonplace, and are being used in an increasingly broad range of applications. The TZGPS system requires you to have a GPS receiver that can plug into PalmOS-based hardware. These are available for the $100 to $200 range from most office-suply and gadget/electronics stores. The TZGPS system reads NMEA Navigation messages output by the GPS hardware, and uses them to display your position on the Palm device. In addition to displaying the position, it has a number of other interesting and useful features (see below).

You can download the current version here at

• Primary Site: http://sourceforge.net/projects/tzgps/
• Secondary Site (older, no longer active): http://www.linas.org/tzgps/ftp/

Other Projects

• Janszoon for MiTAC MGS-110 GPS units.
• PalGar -- Use your Palm to up/download and edit waypoints from a GARmin GPS
• PalmOpenSource Navigation Software is a listing of other Palm GPS software for which the source codee is freely and openly available.
• Navigation and the Palm OS is a listing of other Palm GPS Software.
• The Original TZGPS website

The README file

TZGPS Version 0.2
-----------------
March 2002

TZGPS is a basic GPS application for the PalmOS-based handhelds 
(Palm Pilot, Handspring Visor, etc.)  As of this writing, it is
a fairly basic GPS application, and is not quite suitable for 
the non-technically minded.  Programmers will find this app 
interesting as a base on which to build more sophisticated
PalmOS GPS applications.

TZGPS supports the following features:

-- Decode of a half-dozen NMEA 0183 GPS messages
-- Display of satellite positions
-- Display of latitude, longitude, time, elevation, heading, speed.
-- Database for storing NMEA messages (can be used, for example,
   for recording a wandering path.)
-- Database for logging waypoints (i.e. recording a position,
   and attaching notes and comments.)
-- User interface for waypoints (at the moment, very very crude.
   You can only record waypoints, you can't yet view previously 
   recorded ones.)

Tested GPS Systems:
-------------------
TZGPS is known to work with the following GPS Systems:
-- Magellan GPS Companion for the Handspring Visor
-- TransplantGPS for the Handera 330

Missing features:
-----------------
-- Documentation.
-- User Interface graphing a wandering path.
-- User interface to manage trip logs (there is currently no
   way to delete logs of old trips.)


Bugs:
-----
-- displays only the UTC time, and not the local time.
-- doesn't display how old the last valid GPS reading is.
   (although this is available internally with the 
   get_data_age() subroutine.) 
   Should be modified to be clear about whether reading is 
   current, or old.

License:
--------
TZGPS is covered under the Free Software Foundation GPL version 2 license.
See the included file 'COPYING' for a copy of the license.

History/Provenance:
-------------------
TZGPS was originally developed by Tom Zerucha 
It has been heavily modified/enhanced by Linas Vepstas  
in February 2002.

In March 2002, Daniel Seifert  updated TZGPS to
use the New Serial Manager (allowing to access different serial ports,
for example to use CF GPS cards) and to make use of the high-res screen
of the Handera 330. 

Documentation:
--------------
The radar-like display shows the positions of the GPS satelites in the
sky. (The chart is oriented so that true north is up.)  The size of the 
dots indicates the signal strength (actually, the signal-to-noise ratio,
SNR).  When the squares are filled with black, they merely denote the 
position of the satellite.  When a square has a clear center, it denotes 
that that satellite is beind used for a fix.


Compiling TZGPS:
----------------
You need the following packages to build TZGPS:
prc-tools -- the gcc-based palmos development environment
pilrc -- to compile the GUI resource descriptions