Topic: Topographic Maps PSSA: A/S8.D.1.1

Objective: TLW explain how contour lines show elevation on a map. TLW explain how relief of an area determines the contour interval on a topographic map. TLW list the rules of contour lines. TLW determine elevation using topographic maps.

MI #1: What is a Topographic Map? A topographic map is a map that shows the surface features (or topography) of the Earth using contour lines to represent elevation. Topographic maps show natural features, as well as man-made features.

Mi #2: Contour Lines Contour line are lines that connect points of equal elevation. The shape of a contour line reflects the shape of the land. The spacing of contour lines indicates the slope of the land; the closer the contour lines are together, the steeper the slope.

MI #3: Contour Interval The difference in elevation from one contour line to the next is called contour interval. Relief is the difference between the highest and lowest points on a topographic map.

MI #4: Index Contour A darker, thicker contour line that usually appears as every 5 th line is an index contour. Index contours help make reading a topographic map easier.

MI #5: Reading a Topographic Map Topographic maps use symbols to represent parts of the Earth’s surface. Most maps have a key to explain the symbols. In general, contour lines are brown, cities are pink, and wooded areas are green; most other features (railroads, buildings, etc.) are black.

MI #6: Rules of Contour Lines Contour lines never cross Contour lines that are close together show steep slope, while contour lines that are further apart show gentle slope. Contour lines that cross a valley or stream are “V” shaped; the “V” points toward the area of higher elevation (Upstream). Tops of hills, mountains, etc. are closed circles; depressions are marked with straight lines inside the circle that point downslope.

So What…? Real Life Application Topographic maps are useful for planning man- made structures such as buildings, roads, etc. Topographic maps are also used by hikers to plan routes for hikes.