Study a topographic map from the U.S. Geological Survey or another source to assist in planning an itinerary to a wilderness region. Backpackers and cross-country hikers especially need these maps to route their travels along an efficient route (often with as little change in elevation as possible), avoid obstacles (like landslides, deep canyons and other generally rugged terrain), and locate water sources and potential shelter.
Safety & Survival
Choose a detailed-enough topographic map and keep it handy on treks to ensure your personal safety. Sharing your route with friends and family, not to mention other members of your own party, is made far easier with the detailed geographic information coded in a topographic map. If you do find yourself off-course, injured, beset by rough weather or otherwise threatened, the map can help you find springs, high points (where cellular phone and GPS reception might be stronger), nearby roads and buildings.
Hunting & Fishing
Read the landscape through a topographic map to identify likely locations for game and fish. For example, if you're pursuing elk during a chilly autumn, you might focus on south-facing slopes that can attract thermoregulating animals, not to mention natural bottlenecks of terrain that concentrate moving herds. Adventurous backcountry anglers can seek out high-elevation lakes that may only be accessible by foot.
Professional and Scientific Uses
For planners, topo maps can suggest potentially unstable landscapes --- like landslide slopes, bottomlands or cutbanks and eroding shorelines --- that do not lend themselves easily to development. For botanists and biologists, they can be overlain with other map layers, like vegetation or soil zones, to predict species distribution. Developers might scrutinize such depictions of terrain, in concert with other data, to identify good spots for, say, wind-turbine placement. The applications are as endless as geography's impacts on our lives.
Many people find well-designed topographic maps pleasing works of art. Vintage maps created by hand, even those outdated or inaccurate, can live on as wall decorations. Some old methods of representation, like hachure relief maps (which depict severity of slope with line segments of varying length), still show up in books and articles because of their uniqueness and aesthetic quality.