The latest twist in electronic navigation aids is mobile mapping coupled with a Global Positioning System (GPS) receiver. Not only does GPS tell you exactly where you are, the mapping software lets you view your progress on a screen showing a detailed street-level map.

Delorme offers two products that stand alone or work in conjunction with the other-Street Atlas USA 7.0 and Earthmate GPS. The GPS receiver plugs into a laptop computer and navigates using the Street Atlas software.

Garmin International and Magellan Driver Information Systems both offer a stand-alone GPS receiver and display that runs preloaded software and displays the map on its own screen.

The Magellan Nav 750 even offers voice prompts to tell you when to turn. The Garmin Street Pilot is similar in that the receiver and display are a stand-alone unit into which you load the regional software from an available database of maps called MetroGuide USA.

These units are surprisingly inexpensive and don’t require a laptop computer. But the applications are automobile-specific, which suggests that if you allow yourself to be led down the wrong one-way street, the low bridge around the corner could prove to be a problem.