1. Maps

Regional outfits like Outdoor Trail Maps in Colorado or the ­Appalachian Mountain Club in the Northeast provide local details, such as trail routes. They also have standard cartographic info like elevation, GPS coordinates, and the topographical lines that show terrain contours.

2. Sleeve

Thanks to a zip ­closure with heat-welded seams, the Sea to ­Summit TPU translucent envelope will protect your precious chart in ­water up to 33 feet deep. The 12-by-8.3-inch thermo­plastic urethane case is also freeze-​proof, so it won’t crack. Eyelets provide a way to lash it down.

3. Pencil

Savvy wanderers annotate their guide—say, by adding an X to mark their destination for the day—to make it even more useful. A ­mechanical pencil such as the ­Zebra M-701 stays sharp, its ­stainless-​steel case won’t corrode in moisture, and textured knurling helps you grip it. RELATED: How to find your way out of the woods without tools—or your phone

4. Compass

Use the transparent ­Suunto A-30 compass to orient the map so it’s lined up with magnetic north. Then, measurements on its side will help you interpret the scale so you can figure out that the 1 inch of paper between you and a lake is a really freakin’ long walk in the real world. This article was originally published in the Spring 2019 Transportation issue of Popular Science.