Maps and Navigation

Every survival game has a map. Without one, you wander in circles, walk off a cliff, or never find your way back to base. Real life is the same. Maps are how humans have kept from getting lost for thousands of years.

Scientists put an invisible grid over the whole planet so any spot can have an address.

• Latitude lines run side to side, like the rungs of a ladder ("lat" sounds like "ladder"). They measure how far north or south you are from the equator, which is 0°. The North Pole is 90° N. The South Pole is 90° S.
• Longitude lines run top to bottom, from pole to pole. They measure how far east or west you are from the prime meridian, which is 0° and runs through Greenwich, England. They go up to 180° east or west.

Put the two together and you get coordinates. Idaho Falls sits at roughly 43° N, 112° W. That's your spawn point's address.

Each degree breaks into 60 minutes, and each minute into 60 seconds. Yes, like a clock. No, nobody knows why they did that to us.

Earth spins once every 24 hours. Split 360° by 24 hours and you get 15° per hour. That's why the world is divided into time zones about 15° wide. Idaho Falls is on Mountain Time. When it's noon here, it's 2:00 pm in New York.

Out in the Pacific is the International Date Line, near 180°. Cross it going west and you skip ahead a whole day. Instant time travel. Kind of.

Earth is round. Paper is flat. Try flattening an orange peel without tearing it. You can't. Every flat map stretches or squishes something. These are called map projections.

• Mercator projection: Great for navigation, but it makes places near the poles look huge. Greenland looks as big as Africa. In real life, Africa is about 14 times bigger.
• Equal-area projections: Keep sizes correct but bend shapes.
• Globes: The only truly accurate map. Also impossible to fold into your pocket.

Every good map has a few survival tools built in:

• Legend (key): explains the symbols. Blue lines = rivers, little tents = campgrounds.
• Scale: tells you real distance. "1 inch = 1 mile" means an inch on paper is a mile on the ground.
• Compass rose: shows north, south, east, west.

A topographic map shows the shape of the land, its hills, valleys and cliffs, on a flat page. It does this with contour lines. Each line connects points at the same elevation, or height above sea level.

Here's how to read them:

• Lines close together = steep. Think cliff.
• Lines far apart = gentle slope. Think easy walk.
• Circles inside circles = a hill or mountain.
• Lines that make a V pointing uphill = a stream valley.
• The contour interval is the height difference between lines, like 20 feet each.

Hikers, firefighters, and search-and-rescue teams use topo maps all the time. If you've ever hiked in the Tetons, someone planned that trail with one.

• GPS (Global Positioning System): about 30 satellites orbit Earth. Your phone listens to at least four of them and figures out exactly where you are.
• Remote sensing: satellites and planes photograph and scan Earth from above. That's how we track wildfires, floods, and melting glaciers.
• GIS (Geographic Information Systems): computer maps that stack layers, like roads plus rivers plus population, so you can spot patterns.

Your phone's map app uses all three. You're basically carrying a mapping lab in your pocket.