Magnetic GPS designed for outdoor use always assume a straight line as the route between two points. That might be convenient for airplanes and boats, but it doesn’t take into account cliffs, rivers, streams, fences, and other obstacles on land. GPS receivers designed for automobile navigation are a bit smarter, having built-in databases of road information that’s used in suggesting and measuring appropriate routes from Point A to Point B.
Some GPS receivers come with databases of cities, highways, airports, landmarks, and other geographic features. These are just waypoints stored in memory that you can’t edit or delete to free up memory for new waypoints. Most GPS receivers support mapping. At the very least, a waterproof GPS has a simple plot display, a map page that shows waypoints, tracks (see the upcoming section, “Making Tracks”), and your current position. More advanced (and expensive) GPS receivers support more sophisticated maps; your waypoints and tracks appear along with roads, rivers, bodies of water, and whatever built-in features the map has. When the map page is displayed, you can zoom in, zoom out, and move around the map with an onscreen cursor that you control with buttons on the GPS receiver. A map page can be orientated two ways: so either the top of the screen always faces north or the top of the screen faces the direction you’re traveling. Orientating the screen to the north is probably the easiest if you’re used to working with maps, which usually are orientated with their tops to the north.
A fair number of vehicle GPS tracker owners don’t use routes and find them to be an overrated feature. After all, after you reach your first destination, you can easily select the next location from the waypoint list and be on your way. In addition, if you want to record where you’ve been, just using tracks is much easier.
Don’t confuse a route with an autoroute, which applies to GPS receivers that can provide you with turn-by-turn street directions to a destination you’re driving to. AutoRoute is also the name of a Microsoft European street mapping program. Routes can be created ahead of time or entered while you’re traveling. Like with waypoints, after you create a route, you can delete or edit it, including removing or adding waypoints within legs. Whenever you’re using a route or navigating to a waypoint, you don’t need to leave your GPS receiver on all the time. You can shut it off every now and then to conserve batteries. When you turn the GPS receiver back on, just select the waypoint or route that you were using, and the GPS receiver recalculates your present position and gives you updated information about how to reach your destination. The number of routes and the number of waypoints that a route can consist of vary from one GPS receiver to another. Some inexpensive GPS ID Card don’t support routes, but a high-end consumer GPS unit might have up to 50 routes with up to 125 waypoints in each route.