The GPS data on this web site comes from a Delorme Earthmate receiver located in the rear window of a vehicle and a Garmin Etrak "Basic Yellow" receiver located on top of the dashboard. The units are held in place by velcro.

The "Basic Yellow" is a handheld device that didn't come with a data or power cable. The Earthmate comes with a USB cable so it can be connected to a computer but there wasn't room for a computer so a PDA was used instead which necessitated the use of a serial cable instead of the USB cable.

To collect the data, both GPS units were connected to a combination serial data/car adapter power cable each of which had to be purchased separately from Garmin and Delorme.

COMPUTER and PDA

The Earthmate is connected to an HP Pocket PC running Delorme's Street Atlas USA 2004 Handheld program and creates the .gpl Delorme GPS log file. This file can be played back by Delorme's Street Atlas or Topo on a Computer and can be "imported" by those programs to create a "draw file" (.an1) that can be displayed on the program's map.

The Etrak can keep a record of travel in its internal memory and is referred to as a "track." "Waypoints" can be created and stored in its memory as well. Both the track and waypoints can be transferred to Delorme's programs as "draw files" (.an1) and displayed on the map. Garmin also has a program called "mapsource" which can receive tracks and waypoints from an Etrak GPS and display them on a map. The file extension for the "mapsource" files is .gdb

In addition to its internal memory, the Etrak can send via a serial cable NMEA (National Marine Electronics Association) format data. This data was collected by a MS DOS computer running a data logging program. (This data can also be collected using HyperTerminal.) These files are .txt files with nmea somewhere in the name to differentiate them from .txt files created by the "export" function from the .an1 Delorme "draw files."

POWER:

All units except for the Earthmate has its own battery and can also run directly (or via an inverter) off of the vehicle's accessory/cigarette lighter sockets. To prevent the Earthmate from being reset or interrupted during vehicle restarts, it was plugged into a portable battery setup that has a cigarette lighter socket to run portable devices so you don't run the car battery down. The portable battery setup can be recharged from the car or from a 110 AC adapter.

The following photos can further explain things.

• Photo of some of the equipment used.
• Photo showing what to set in HyperTerminal.
• Photo showing HyperTerminal in use collecting NMEA data.
• Photo showing the Garmin GPS unit on the dash.
• Photo showing the back side of the portable. Note the seat belt.
• Photo showing the front side of the portable. Note the seat belt.