Here's how it works:
* Contour lines: These are lines that connect points of equal elevation on the map.
* Contour interval: This is the vertical distance between two adjacent contour lines. For example, a contour interval of 20 feet means that each contour line represents a 20-foot change in elevation.
To find the difference in elevation between two points, count the number of contour lines between them and multiply that number by the contour interval.
Example:
If two adjacent contour lines are 20 feet apart (contour interval = 20 feet), and there are 3 contour lines between two points, the difference in elevation between those points is 60 feet (3 lines x 20 feet/line).
