162 Part II — Software Hacks

You may also find a positional error. Positional errors are likely caused by GPS errors or communication errors. Try these steps to resolve the problem:

1.Ensure that the cable is properly connected at both ends. Problems here can cause data corruption and a degradation of signal quality.

2.Verify that the GPS has a clear view of the sky and is receiving a good signal.

USB-to-Serial Converters

If you are using a USB-to-serial converter, you might encounter a few problems specific to your setup.

For example, you might find that the number assigned to the port creates changes occasionally, and you might have to reconfigure any software you are using if this has happens.

Another problem is that a USB-to-serial converter can assign ports from COM 1 to COM 255. However, some software packages can only use ports 1 to 4. Most modern applications allow you to choose any active port for GPS communication, but if you use an older software package you might be limited to ports 1, 2, 3, or 4.

Only versions 4.0 and later of the Garmin MapSource mapping program will interface with a GPS through a USB-to-serial connector. Any previous versions will fail to work.

USB-to-serial converters are not supported in Windows 95, even the OSR 2.1 version that included USB support. You will need a minimum of Windows 98.

Summary

This chapter looked at problems you might encounter when transferring data between the GPS and a PC or handheld device. As I’ve said a few times, you don’t have to have a connection in place, but it makes life a lot easier and enables you to process and display data in a much more versatile and customizable way than is possible with most GPS units.

If you are unfortunate enough to have problems with your connection, following either the generic or specific instructions in this chapter should help you fix the problem and get your system working again.

Data Hacking

part

in this part

Chapter 8

GPS Data

Chapter 9

Examining the Data

Chapter 10

More Data Tricks