Anatomy of a Topo Map Contour Lines The thin brown lines snaking around a topographic map are contour lines. All points along the same contour line are at the same elevation above sea level. Think ...

Knowing how to read a map is a skill much like building a fire, riding a horse or knowing which plants will kill or cure you; a relic from a simpler time, before Google had all the answers.

The USGS also uses “shake stations” — denoted by colored circles in the map above — to measure the magnitude of earthquakes across the country, and it process the data to make contour maps.

A topo map with a scale of 1:10,000 shows a smaller area and is more detailed than a map with a 1:25,000 scale because it is more zoomed in. It's important to know how detailed your map is when ...