During the past decade, the use of marine Global Positioning System units has evolved from laying down get-you-close waypoints to pinpoint angling accuracy.

The present array of GPS models, from uncomplicated hand-held versions to massive-screened units with built-in memory to match, are valuable companions in a diversity of angling situations.

Creek fishing

So you think a GPS is of no value in creek situations? Well, that's not really the case.

Whether exploring a wadable trout stream away from the road or investigating a larger creek for smallmouth bass possibilities, a hand-held GPS is tremendously useful.

Say you want to look into a loop of creek that swings away from the road. Before parking your vehicle at one end of the loop, drive to the spot where the creek retouches the road, and mark it with a waypoint. That way you can be assured of finding the takeout spot when you reach it.

Takeouts can look a lot different from the creek, as opposed to up on the road, especially if trees, brush or a high bank is involved.

By having a takeout you don't have to backtrack over "used" water. Often, the walk back to the car is much shorter along the road, as compared to the creek's course.

Many hand-held units now come with basic background map software or accept memory chips containing it. With such information loaded into your unit, if you are walking a stream, or floating it in a canoe, kayak or inflatable pontoon, you can see where you are in conjunction with nearby roads.

If you find a great spot during a float, you now have an idea of how to access it on foot during a future trip, if you so desire and if you receive the landowner's permission.

Handheld GPSs usually run on a couple of AA batteries. A unit will eat up a set of fresh batteries during a full day, so be sure to carry spares.

Cutting a lake trail

The ability to lay down a trail — a history of your boat's movements — is one of the most useful features of console-mounted GPS units.

For the troller, trails show what water has been covered and what areas still need to be explored. Casters can lay down a trail along the edge of a structure, such as a point or hump, then reference the trail to keep the boat the proper distance from the spot as the place is fished. It's like having a string of electronic marker buoys in place to help with boat positioning.

Plotters with color displays give you the option of changing the color of the trail during the day's fishing, a useful feature when trying to distinguish areas you fished a couple of hours ago, compared to where you currently are.

Most GPS units feature an option that allows the user to drop event markers, also called icons. An array of symbols is available, depending on the unit. Icons are great for making things like schools of baitfish or a turn in a weedline.

Hit the icon button and the unit will store the location in its memory. Then you can scroll through the symbol options before making a selection. When you do so, it will place the icon at the position you were when you first hit the icon button.

Electronic Mapping

Perhaps greatest attribute of marine GPS units is realized when used in concert with an electronic lake chart program.

Though such software comes pre-installed in some high-end units, more typically a slot is available that accepts programs from third-party mapping companies. Not all units have this capability, and there are several media formats available.

When shopping around, be sure a program you are considering works in your unit. Such information is readily available on manufacturers' websites.

Electronic lake charts place a background map of the lake you are fishing on your screen. The most useful feature is contour lines, the detail of which varies greatly, based on the information used to form the map.

Just like hardcopy maps, some are detailed and accurate, other not so much. Expect the quality of such electronic charts to improve as companies survey lakes, rather than relying on the data of hardcopy maps.

I've used Navionics Premium HotMaps the past couple of years and have found the charts to be quite accurate, especially the ones based on Fishing Hotspots maps.