More features

Some features in the chart plotter itself are not yet documented such as: If you have maps of different scale over the same area pressing the key 'o' (with the chart window selected, not the dos shell) will choose an overview map and 'i' will choose the detailed map. I have plans to add a menu for this.

Viewing a log file

It is possible to playback a previous run. The file can either be a raw NMEA log file or it can be the log file saved by the chartplotter program itself.

The paths in this instruction may be different on your computer!
Here I assume that:
SUNīs java SDK version 1.4.2 is installed in C:\j2sdk1.4.2_05
chartplotter is in c:\java
charts are in c:\charts
log file is in c:\temp\nmea.log

Install java (if you have older than 1.4.2 you need to uppgrade)

Install the chart plotter, see:

Calibrate some charts (I plan to make a wizard so that this step will be more user friendly some day).

Open a dos shell

give the path to java:
set path=%PATH%;C:\j2sdk1.4.2_05\bin;

give the classpath to chartplotter:
set CLASSPATH=.;c:\java;c:\java\ChartPlotter.jar;

Go to the folder where the chart are stored
cd c:\charts

Start the chart plotter giving the path to the log file:
java ChartPlotter -rc:\temp\nmea.log

Manual configuration

If you made some small mistake when calibrating a chart using the calibrate chart program then you dont have to recalibrate it all over. It is possible to patch in the cfg file itself since it is an ascii text file. This is the format:

How to start the program

You will need to use the CalibrateChart program first to calibrat at least one chart. Then the ChartPlotter program can be used.

Windows Example

We recomend using the bat files ChartPlotter.bat and CalibrateChart.bat to start respective program.

These can be downloded from the download page. These bat files might need to be modified with whatever paths and java versions you use. There are comments in these files so it should be quite self explaining.


You will need to translate the bat files into shell scripts.


Usage: java ChartPlotter [switches] [<file name>]

<file name>
The name of the file with reference points (charts.dat is default).


The name of the com port to use is <n> (On Windows COM1 is default).

List more switches.


The GPS receiver needs to have an NMEA compatible serial port interface. NMEA is a one way protocol so the PC can not tell the GPS to start sending NMEA. Check your GPS receiver’s documentation on how to start sending data in NMEA format from your GPS. For Garmin receivers this is done under communication

NMEA is a one way protocol. It is not possible for the PC to order the GPS to start sending positions in NMEA format. This must be done manualy. A common problem.


Here is our list of GPS related sites.


If you like this software please let us know. Send comments or questions to: