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# Chapter 2:3 Maps

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• 1.
• 2. Chapter: Views of Earth Table of Contents Section 3: Maps Section 1: Landforms Section 2: Viewpoints
• 3. Map Projections
• Maps are models of Earth’s surface.
• Scientists use maps to locate various places and to show the distribution of various features or types of materials.
Maps 3
• For example, an Earth scientist might use a map to plot the distribution of a certain type of rock.
• 4. Map Projections
• A map projection is made when points and lines on a globe’s surface are transferred onto paper.
• All types of projections distort the shape of landmasses or their areas.
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• 5. Mercator Projection
• Mercator (mer KAY ter) projections are used mainly on ships.
• They project correct shapes of continents, but the areas are distorted .
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• Lines of longitude are projected onto the map parallel to each other.
• When longitude lines are projected as parallel, areas near the poles appear bigger than they are.
• 6. Robinson Projection
• A Robinson projection shows accurate continent shapes and more accurate land areas.
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• 7. Conic Projection
• Conic projections often are used to produce maps of small areas.
• Half of the world at any one time.
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• 8. Conic Projection
• Conic projections are made by projecting points and lines from a globe onto a cone.
Maps 3 Click image to view movie.
• 9. Topographic Maps
• A topographic map models the changes in elevation of Earth’s surface.
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• With such a map, you can determine your location relative to identifiable natural features.
• Topographic maps also indicate cultural features such as roads, cities, dams, and other structures built by people.
• 10. Contour Lines
• A contour line is a line on a map that connects points of equal elevation.
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• The difference in elevation between two side-by-side contour lines is called contour interval.
• 11. Contour Lines
• In mountainous areas, the contour lines are close together.
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• However, if the change in elevation is slight, the contour lines will be far apart.
• Some contour lines, called index contours, are marked with their elevation.
• 12. Map Scale
• The map scale is the relationship between the distances on the map and distances on Earth’s surface.
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• Scale often is represented as a ratio.
• A map scale also can be shown in the form of a small bar that is divided into sections and scaled down to match real distances on Earth.
• 13. Map Legend
• A map legend explains what the symbols used on the map mean.
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• 14. Geologic Maps
• Geologic maps show the arrangement and types of rocks at Earth’s surface.
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• Using geologic maps and data collected from rock exposures, a geologist can infer how rock layers might have looked below Earth’s surface.
• 15. Geologic Maps
• The block diagram is a 3-D model that illustrates a solid section of Earth.
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• The top surface of the block is the geologic map.
• Side views of the block are called cross sections , which are derived from the surface map.
• 16. Three-Dimensional Maps
• To visualize Earth three dimensionally, scientists often rely on computers.
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• Using computers, information is digitized to create a three-dimensional view of features such as rock layers or river systems.
• Digitizing is a process by which points are plotted on a coordinate grid.
• 17. Map Uses
• If you wanted to determine New Zealand’s location relative to Canada, you probably would examine a Mercator projection.
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• If you wanted to travel across the country, you would rely on a road map, or conic projection.
• To climb the highest peak in your region, you would take along a topographic map.