What do contour lines on topography maps represent?
If you look at a topographic map, the solid, curving lines are contour lines that indicate the elevation and shape of terrain. The elevation change between any two adjacent countour lines (the contour interval) is the same everywhere on a given map. If the contour interval is 10 feet, the elevation changes 10 feet within these adjacent lines. Contour lines close together indicate steep mountainsides or cliffs. Gentle sloping hills or flat plains have contours farther apart from each other. Experienced map readers can look at the contours and visualize the three-dimensional shape of the land. “Cutting” a line through the contours enables the map reader to draw a profile of that section of the mountain or plateau. Hachure marks along a contour show depressions, for example, of a crater or the mouth of a volcano. Who uses topography maps? Hikers, campers, snow skiers, city and county planners, the Fish and Wildlife Service, Forest Service, miners, loggers, highway planners and constructio
