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Aim: How can we read topographic maps?. Do Now: Which reference line passes through both the geographic North Pole and the geographic South Pole? . (1) 0° latitude. (3)Tropic of Cancer. (2) 0° longitude. (4) Tropic of Capricorn. Contour Maps.
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Aim: How can we read topographic maps? Do Now: Which reference line passes through both the geographic North Pole and the geographic South Pole? (1) 0° latitude (3)Tropic of Cancer (2) 0° longitude (4) Tropic of Capricorn
Contour Maps • The most commonly used contour map is the topographic map. • Topographic maps portray a three-dimensional view of Earth (elevation map). • Shows physical features such as hills, valleys, cliffs, and depressions.
The more area covered on a map of latitude/longitude the less detail it shows. • Map Scale: shows a proportion of what distance is on a map to what distance is on Earth. Example: 1:24,000 For every 1” on a map = 24,000” on Earth.
Map Legend: refer to handout pg. A17 for further details. • Map Colors: Blue = Water Red = Major Roadways Black = Buildings Green = Vegetation Brown = Contour Lines White = Undeveloped Land
Pink = Urban Development (Housing) Purple = Revisions
Contour Interval: Vertical distance between two contour lines. The smaller the contour intervals the lower the relief. The greater the contour intervals the higher the relief.
Benchmarks gives the exact elevation of a single point. 540 540
Gradient: closer the contour lines the steeper the gradient.
Why are some of the lines darkened? • Every 4th or 5th contour line is darkened, so it is easier to read.
How does a contour map show the direction of a river system? • Contour lines bend upstream when crossing a river. • The river flows in the opposite direction.
What are hachure marks? • An area of depression (land that sinks).
How can you determine a hilltop? • Concentric circles getting smaller
How can you determine direction? N • Using a compass is the best way to describe direction. NW NE W E SW SE S
Summary What is the purpose of a topographic map? How does a topographic map tell you the direction of a river or creek? What are hachure marks? How can you tell a hilltop on a topographic map?