Topographic Map - Contour Lines
Contour maps make a valuable tool for understanding the elevation of your land and surrounding terrain. Contour lines are lines drawn on a map connecting points of equal elevation, meaning if you physically walked along the contour line, your height above sea level would remain constant. In order to keep things simple, topographic maps show lines for certain elevations only. These lines are evenly spaced apart. We call this spacing the contour interval. For example, the map below uses a 10m contour interval, you will see contour lines for every 10 meters of elevation. Different maps use different intervals, depending on the topography and how precise the mapping needs to be. How a topographic map represents the terrain. To make topographic maps easier to read, every fifth contour line is an index contour. Because it's impractical to mark the elevation of every contour line on the map, the index contour lines are the only ones labeled. The index contours are a darker o...