Returning to the trail head after a hike.

Most (if not all) units will allow you to mark your current position, this is variously called a Waypoint, a Favourite or a MOB (Man Over Board) point, this will allow your GPS to point in a straight line back to this marked position, however it can be dangerous to follow this straight line path without knowing the terrain in between the two points, most units will also plot a track of where you have been (also called a breadcrumb trail of track back), this track, which on some models is displayed against an in build map can be followed using all the twists and turns made on the initial trip, is is slower than taking a direct line back to your staring point, but is much safer, as all the terrain covered is already known to the user, so you will be avoiding any unknown pitfalls