Early GPS units were pretty clunky by today's standards - and approximately 30 times more expensive. Today's units are faster, more accurate, and most importantly, have a lot more memory. Now, we can look at a detailed on-screen map of the area around us and see ourselves on it. We can also see the locations of places we visited and saved as waypoints, and getting between them is as simple as selecting one with a cursor and hitting a Go-To button.

But what if we want to explore new territory, go where we haven't been and find our way back? Such a day trip can be made easier by using the track-plot feature found on even the smallest, least-expensive hand-held units.

First, save your starting location as a waypoint. This can be where you parked your car, launched your boat or the trailhead where you started walking or pedaling. Next, switch to the chart-plotter screen, if the unit has one, or the track-plotter screen if it does not, and make sure the track feature is turned on. It leaves a trail of electronic breadcrumbs that appears as a dotted line on the screen as you travel.

Most units let you adjust how often an electronic crumb is dropped, by time or by distance. The total number of dots a unit can set is limited by its memory, and your owner's manual will tell you how many points a plot trail can have.

If you plan to go only a few miles, you can set the unit to mark a dot as often as possible. If you think you might go 50-100 miles, you'll need to set the unit to mark a dot less often. This is important, because when the maximum number of dots a unit can save is reached, it starts erasing the oldest ones as it saves new ones, and we need to be able to follow a trail all the way back to its beginning.

It can take a while to thread your way through a shallow bay or across a flat in your boat, but once a safe path is recorded by your track plotter, you can easily follow it in reverse to get back to the dock. You can also permanently save a plot trail, name it and then follow it in either direction whenever you want.

Hiking or biking through a network of trails can also be confusing, but following your plotter trail in reverse leads you back out the way you came in, even through fog or darkness.

Following a plot trail using the track plotter screen is easy, you just steer or walk in the direction that prints your new track right on top of your old one. Some units have a feature you can engage to follow the plot trail you are on in reverse. Instead of having to place your new plot trail on top of the old one, it lets you use the unit's graphic guidance screen that shows the path ahead like a highway and directs you to go right or left to stay on it, all the way to your starting point.

Automatic routing is another neat feature found on many units. It looks at your plot trail, sets as many waypoints on it as necessary to allow for straight-line travel between them, and then saves the whole works as a route that you can name.

Always keep in mind that GPS accuracy varies, and you should use plot trails as guidelines, not as set-in-stone trails with pinpoint accuracy. Carry along a compass and a paper map, and never allow your life to depend on something powered by batteries!