Road Travel


Thereís a lot of Road Warriors out there, and almost all have notebook computers these days. When I travel for work, I use a Garmin GPS 12XL, and a PC compatible notebook equipped with a CD-ROM. For most comprehensive road map packages, a CD-ROM is necessary, as that medium allows for the fast retrieval of data for high resolution maps. In some cases, only the portion of the map needed per trip can be copied from the CD to a 3 Ĺ floppy, to be used in a notebook without a CD-ROM. In addition to the notebook computer and the GPS unit, I go equipped with a power/data cable for my GPS, which provides the power to the GPS from the cigarette lighter, and the data connection to the computer, as well as a 12VDC/120VAC power inverter to power the computer, and a cigarette plug with dual receptacles, to power both the computer and the GPS unit. This reduces wear on the batteries, both in the GPS and the computer.


There are several road map packages available out there, for both PC and Mac users. I personally use Street Atlas 5.0 by DeLorme, and the graphics and description will feature that package as a result. Other packages will have many similar features, and this is intended more to show the capabilities of the GPS/Computer combination than to push any one particular package.

So now, Where do you want to go today?

The first step is planning a route. You know your starting point; you know your ending point. Street Atlas allows you to pick your origination and destination points, down to the street address, and then will choose a route for you based upon either speed, distance, or scenery, as well as allow you to fine tune your route by picking your own roads for portions of the trip. In this case, I was flying into Sioux City, IA, renting a car, and driving to Sioux Center, IA, which is approximately 50 miles away. This is a rather simple route, which is good, as it allowed me to capture a few screen shots along the way. It works equally as well, and is even more of a tool, in larger metropolitan areas. The route is shown by the wide shaded line on the map. There is also a text description of the route, with the road names, distances, and estimated time, as well as some exit/entrance ramp info. Also, once the route is created on the software, it can be uploaded into the GPS unit if desired.

Prepare to go!

As I said earlier, the setup I use involves a dual receptacle cigarette lighter plug. I plug it into the cigarette lighter receptacle on the vehicle, and plug the 12VDC/120VAC inverter into one of the receptacles. In the other receptacle, I plug the power branch of the power/data cable for the GPS unit. Some GPS units require a lower voltage than the standard 12VDC from the vehicleís cigarette lighter receptacle, in which case a regulator must be installed in the cable to lower the input voltage to the GPS unit. I then plug the data branch of the power/data cable into the notebook computer, and plug the computerís AC plug into the inverter. This whole setup can also be done with just a data cable, letting the GPS and computer run off batteries, for short trips. Itís now time to fire up the GPS and computer!

Set up your Interface

In order to track yourself on the computer, the GPS unit and computer must have their interfaces compatibly configured. In most road map/GPS packages, there are several choices of interface configurations. Generally, the GPS manufacturer specific interface (Garmin, Magellan, Trimble, etc.) is used for upload/download applications, such as the uploading of the route from the computer to the GPS which was briefly mentioned in the route planning section. For real time tracking on the computer, however, you will want to set up both the computer and the GPS for NMEA interface. Make sure that the baud rates match each other, and that the Com Port corresponding to your serial port is correctly identified for your computer.

Hit the Road!

If your setup is correct, and your GPS has a lock on the satellites, your screen should indicate your current location. With Street Atlas, your position while stationary is indicated by a green circle. Once you begin moving, the screen will be updated reflecting your movement, in this case with a green arrow. In Street Atlas, the colors will change from green to yellow if your lock degrades to only 3 satellites, and if you lose your lock there will be a red circle at the location of signal loss. With the file your route was saved to on your screen, simply follow the route with your position indicator. In this case, the route is identified by the wide shaded line, and the position and direction of movement is indicated by the green arrows. Street Atlas also provides a "GPS Map Feature" which allows you to invert the colors on the screen, in many cases making it easier to view the map and your position. You can also zoom in or out to provide the desired view of the map, and the map should update as your position scrolls off. At this point, just follow the route to your destination! You can see when youíre approaching a road change, an exit ramp, etc., and can get updated time and distance information.

Just for Fun!

When I travel by commercial air, I often enjoy tracking the planeís route on Street Atlas. I generally fly Northwest Airlines, as Iím fairly close to Minneapolis/St.Paul, and GPS units are approved devices for use on that airline, once the altitude is reached where electronic devices can be used. In addition to allow me to know where I am, I can monitor the speed and altitude of the plane, and spend some more relaxed time getting use to features available in the software and GPS unit. As on the road, position and direction are displayed on the map with a green arrow. A trick that I stumbled across, to get a faster 3D lock on the satellites, is to enter the estimated altitude/elevation in the GPS unit. This seems to speed up the acquisition of satellite locks, and get your location on the screen faster.

One of the screens available in Street Atlas, is "Monitor GPS." This screen allows you to monitor speed, location, heading, and elevation. Also, there is a button on that screen that allows you to access "Satellite Status." Satellite status displays the available satellites according to your position, with the satellites you are locked on to represented in green, while the non-locked satellites are represented in gray. The satellite list displays the satellite number, the elevation, the azimuth, and the signal-to-noise ratio for the available satellites.

Following the trip, the entire track can be viewed in a couple of different ways. The first is through Street Atlas itself. In Street Atlas 5.0, you can save the track log in a .gpl file. This can then be imported, and will display the track on the map. You can also change the properties of the line representing the track, with a right mouse button click on the line. Another way of displaying your track, is to download the track from the GPS unit. Obviously, in order to do this, you will need to change your interface settings on both the computer and the GPS unit, and your GPS unit would have had to be set up to record a track log prior to your trip.