Ya Gotta Be Able To See ItAnyone who reads this column regularly is familiar with my mantra about GPS. Without data to use with your GPS, all you have is a $200 speedometer. I have commented regularly about the lack of stand-alone GPS plotters or navigators with a built-in usable database. When Garmin issued its new MapSource United States Topo product, I was jazzed. The box says this product is "comparable to the U.S. Geological Survey's 1:100,000 scale paper maps
"Garmin allowed me to evaluate the MapSource data on its two best machines for data display, the GPS III+ and the ColorMap StreetPilot. A review of the GPS III+ appeared in the Sept. 2000 issue, so I will only mention that I like the machine.
The ColorMap StreetPilot has a very bright 1.8x3.3-inch display and was designed to be used as a street navigator using vector maps. It started life with a built-in database with rather expensive pre-programmed data cartridges available. These ROMs provided street-level, local detail. Garmin subsequently began offering larger-capacity data cartridges and its MapSource CDs. With this combination, you can load the StreetPilot with street-level detail for anywhere in the country. The StreetPilot will not, however, navigate you to a given location. If you create waypoints from your point of origin to your destination, the StreetPilot will navigate you in the same manner as most recreational GPS units.
The data set in the U.S. Topo possesses a lot of information. However, it is not the equivalent of a USGS 1:100,000 map in topographic detail. The quality of data is slightly inferior to Delorme's TopoUSA product. When the program is operating on a good laptop or desktop computer, the data is clear and very detailed. To load the MapSource data into your Garmin unit, you simply set the GPS receiver to the proper data mode and click the portions of the topo map you desire. The software advises you of file size status. This is critical because Garmin units have varying memory capacity.
Herein lies the rub: There is too much data for the unit's screen to display. The StreetPilot and GPS III+ might have displays appropriate for vector street data. (I did not evaluate this data.) The topo data is more suited to displays with higher pixel density than these units. Both units provide a means of adjusting the level of detail shown. This is to avoid clutter in large scales, while allowing you to see needed detail at small scales. However, neither machine provides a quick, one- or two-button solution to the problem. Therefore, scale zooming requires close attention to the unit (at the cost of attention to the trail).
My executive summary? The maps are too hard to read on the trail. The StreetAtlas' cool screen is not enough to overcome its other inadequacies for trail use. The GPS III+ has a good screen and user-programmable tabular displays, which makes a great GPS receiver. But then again, the amount of data provided by MapSource United States Topo overwhelms it.
I still maintain that a PC is the less expensive way to have a GPS topo plotter in your truck. Let's face it: You need a PC to upload topo data into your GPS, so you aren't saving any money. Just space.
Wide Area Augmentation SystemWAAS is the Federal Aviation Administration's effort to provide Differential GPS to the aviation community. Some have said that the service will provide DGPS marine-grade location service all over the country. Do not bet on it.
First of all, this is a project headed by the FAA. Therefore, it is years late and way over budget. Second, it appears to not work as well as hoped. Third, it is designed for use in airplanes. Therefore, the equipment required to obtain the WAAS signal will be priced at aviation levels. (Read: really expensive.) Fourth, the signals will probably not reach into the holes into which we drive off road. Fifth, with S/A turned off, your run-of-the-mill GPS is accurate to about 100 feet. That's good enough.
So, to those who have looked to WAAS as the next latest, greatest navigation idea, I have this one suggestion: Buy a good map.