Geography
How Topographical Maps Represent Relief Through Contour Intervals
Quick fact
On a map with a 40-foot contour interval, a trail that crosses 10 contour lines in a mile climbs 400 feet—but on a map with a 100-foot interval, the same number of lines would mean a 1,000-foot climb, showing how intervals change the apparent steepness.
Why this is interesting
Ever unfolded a topo map and felt the lines look like a secret code? Each ring tells you exactly how high you'll climb—if you know the one number that cracks it all.