Who needs a map when you have GPS? Today, many hikers rely on global positioning systems, either on a smart phone or a dedicated device. No doubt, GPS has advantages. It records your movements and shows you where you've been, helping you to backtrack if you get lost. It works at night or in fog when visibility is limited. The devices are compact and versatile, no folding and unfolding a map.
But even if you have a GPS device, you should plan to take along a map on any extended day hike or backpacking journey. Batteries can go dead; devices can malfunction. And not all GPS devices show hiking trails and terrain details.
A topographical map indicates changes in elevation through contour lines and gives details of hiking trails. It lets you orient yourself in relation to landmarks. Reading a topo map and using a compass are basic skills for serious hikers. It's also handy to know how to get your bearings according to star formations, in case you get lost after dark.
The National Park Service offers trail descriptions and topographical maps that you can download from the Internet [source: NPS Trail]. Many commercial versions of topographical maps are also available. Look for a map printed on waterproof, tear-resistant paper that you can fold to a convenient size. Make sure it's been revised recently, as routes and conditions on the hiking trails can change.
A guidebook that describes hiking trails and major sights of the park can also be useful. You could fill a backpack with all the books available. They cover easy hikes, must-do hikes, difficult hikes and everything in between. Some are dedicated to a single hike, some cover the entire park. Choose according to your hiking plans.
Guided hikes are another way to go. You can schedule day hikes or overnight excursions with experienced and knowledgeable guides to show you the ropes and explain what you're seeing [source: Yosemite Conservancy].
If you ever do get lost while hiking, don't assume your cell phone or satellite phone will work in the wilderness. It's critical that you let someone know where you're going and when you'll return. Take warm clothing and rain gear in case you have to spend the night. Remain calm -- panic is a serious danger when you become disoriented. Stay put or try to find the trail you were on; never try to blaze a new path back.
Most hikers cover Yosemite's trails with aplomb. What are the most popular hiking trails in Yosemite? You'll find out in the next section.