# topographic maps. lesson objectives define a topographic map and state its uses. define a...

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• Slide 1
• Topographic Maps
• Slide 2
• Lesson Objectives Define a topographic map and state its uses. Define a topographic map and state its uses. Describe how contour lines show the elevations, shape, and slope of the land. Describe how contour lines show the elevations, shape, and slope of the land. Identify the meanings of some symbols and colors used on topographic maps. Identify the meanings of some symbols and colors used on topographic maps.
• Slide 3
• What is a topographic map? A topographic map, also known as a contour map, is a map that shows the shape of the land using contour line. A topographic map, also known as a contour map, is a map that shows the shape of the land using contour line.
• Slide 4
• Other Topographic Terms Map scale compares distances on the map with distances on earth. Map scale compares distances on the map with distances on earth. Legend explains symbols used on the map. Legend explains symbols used on the map. Index contours contour lines that are labeled to help you find the contour interval. Index contours contour lines that are labeled to help you find the contour interval.
• Slide 5
• It is a map that shows an elevation field, meaning how high and low the ground is in relation to sea level.
• Slide 6
• What is a benchmark? A benchmark is a point where exact elevation is known and is marked with a brass or aluminum plate. It is marked BM on the map with the elevation numbers given in feet. A benchmark is a point where exact elevation is known and is marked with a brass or aluminum plate. It is marked BM on the map with the elevation numbers given in feet. Benchmarks are useful to help determine contour lines. Benchmarks are useful to help determine contour lines.
• Slide 7
• What are contour lines? Contour lines are lines that connect points that are of the same elevation. Contour lines are lines that connect points that are of the same elevation. They show the exact elevation, the shape of the land, and the steepness of the lands slope. They show the exact elevation, the shape of the land, and the steepness of the lands slope. Contour lines never touch or cross. Contour lines never touch or cross.
• Slide 8
• What is a contour interval? A contour interval is the difference in elevation between two contour lines that are side by side. A contour interval is the difference in elevation between two contour lines that are side by side.
• Slide 9
• Remember that a contour interval is not the distance between the two lines to get the distance you need to use the map scale. Remember that a contour interval is not the distance between the two lines to get the distance you need to use the map scale.
• Slide 10
• What do the dark colored contour lines mean? The dark colored contour lines represent every fifth contour line to make it easier to read the map. The dark colored contour lines represent every fifth contour line to make it easier to read the map.
• Slide 11
• What if my contour lines are close together? If the contour lines are close together, then that indicates that area has a steep slope. If the contour lines are close together, then that indicates that area has a steep slope.
• Slide 12
• What if my contour lines are far apart? If the contour lines are far apart, then that indicates the land has a gentle slope (low slope). If the contour lines are far apart, then that indicates the land has a gentle slope (low slope).
• Slide 13
• More on Contour Lines Contour lines form Vs that point upstream when they cross a stream. Contour lines form Vs that point upstream when they cross a stream. It is important to remember that they point in the opposite direction as the flow of water. It is important to remember that they point in the opposite direction as the flow of water.
• Slide 14
• What do depressions in the map look like? A depression, such as the inside of a dead volcano, is represented by Hachure lines. A depression, such as the inside of a dead volcano, is represented by Hachure lines.
• Slide 15
• What do the colors on the topographic map represent? Blue lines/shapes - represent water features, such as streams and lakes. Blue lines/shapes - represent water features, such as streams and lakes. Brown contour lines Brown contour lines Black Roads, buildings, railroads, other man made objects. Black Roads, buildings, railroads, other man made objects. Green Woodland areas Green Woodland areas Red - Highways Red - Highways
• Slide 16
• Slide 17
• Slide 18
• Now that I know what a topographic map is, how do I read it? 1. First determine the contour interval (the distance between each contour line) 2. Then determine the map scale (usually at the bottom of the map) 3. Identify any hills or depressions 4. Use the legend to identify man made features.
• Slide 19
• Reading a topographic map cont. Look for areas where the contour lines are close together they indicate a steep area. Look for areas where the contour lines are close together they indicate a steep area. Look for areas where the contour lines are spread apart they indicate a gentle slope. Look for areas where the contour lines are spread apart they indicate a gentle slope.
• Slide 20
• Review Questions How are contour lines drawn on maps? How are contour lines drawn on maps? How does a contour map show whether a slope is gentle or steep? How does a contour map show whether a slope is gentle or steep? What is a benchmark? What is a benchmark? How is a benchmark shown on a map? How is a benchmark shown on a map? How is distance measured on a contour map? How is distance measured on a contour map?

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