Trouble shooting

Java version

Check if correct java is installed? If you use JDK (or JRE) you need 1.1.8 or later.
In a command window type:
java -version

It should say something like:
java version "1.1.8"

Incorrect path

Java will use the environment variable CLASSPATH to find the java classes. If java say:
Can't find class ChartPlotter

Then check the CLASSPATH variable like this (windows):

You should get something like this:

Note the paths in the line above can be different depending on installation.

Now check if the files above exist (use the path you got above not the one shown here):
dir c:\java\
dir c:\Program\jdk\bin\comm.jar

No data from GPS

If it don't work use a terminal emulator (such as HyperTerminal in Windows) to see if the GPS is sending anything. If it is check if it sends lines beginning with "$GPGLL" etc and if there is position data in that line.

Set the com port to 4800 baud, 8 data, 1 stop, no parity.

Some GPSes send data in 9600 baud. Check the documentation for your GPS.

If its sends nothing check the cable and the documentation for your GPS on how to make it send NMEA.

If you get this message (more than just occationally):
line was not nmea
then the GPS is perhaps using something else than NMEA.

If you get a lot of:
wrong checksum in line
Then perhapps you have a bad cable.

If you have a cable with a 9 pin DSUB contact: The PC will expect to receive data on pin 2. This can be verifyed with a voltage meter. There should be 5-12 V AC between this pin and pin 5 (GND).

File not found

If a file is not found the program prints something like the following line:
ChartThread: charts.dat
You need to be in the same folder as the charts.dat when you start the program. If not try cd to that folder.

If an image file (usually a .jpg file) is missing you might get just a blank window.

Port not found

If you use a GPS connected via USB you need to connect and start the GPS befor starting the program (but after starting windows, if you connect and start the GPS before starting windows then windows may think it is a mouse).

Known bugs

It probably won't work to have reference points on both sides of the datum line. A workaround is to use two sets of reference points for the same chart image file.

On Windows 95 and 98 it only works if you have the communications API installed. Using this API is no longer supported by this ChartPlotter so if you use Windows 9x you need to use version 0.18 of this ChartPlotter.