Chapter 6: Views of EarthSection 3: Maps

Mr. MotukGeneral Science

I. How are Maps Used?A. Maps are used to model the Earth’s

Surface. B. Maps are made using projections.

1. Making a map of the Earth is difficult because you are placing a round sphere on flat paper.

2. All maps have some type of distortion. a. Either distorted shape or distorted area.

II. Types of Map ProjectionsA. Mercator Projection

1. Represents continental shapes correctly. 2. Areas of distortion: Polar regions get stretched out.3. Forms a grid of parallel lines of latitude and

longitude. 4. Mainly used for navigation.

a. Airplanes and Boats.

B. Robinson Projection:1. Accurate continental shapes and areas. 2. Distorts Polar region only. 3. Displays Earth as a flat top and bottom oval.

C. Conic Projection:1. Used to project maps of small areas. 2. Mainly used for Roads and Weather maps. 3. Produced by projecting latitude and longitude

onto a cone. 4. Distorts latitudinal lines. (They arc)

D. Topographic Maps1. Map showing detailed elevations for an area. 2. Project height onto a flat page using contour

lines. a. Contour lines: connect different areas of equal

elevation. b. Contour interval: difference between contour

lines. c. Index contours: lines marked with an elevation.

E. Using Contour Maps1. Contour lines never cross!!!!2. Contour lines close around hills, basins, or

depressions. 3. Contour lines form V’s that point upstream. 4. A MAP LEGEND tells common symbols. 5. A MAP SCALE tells ratios for determining distance.

TYPICAL MAP LEGEND

TOPOGRAPHIC MAP: HARRISBURG

F. Landsat Satellites1. Detect different wavelengths of energy

reflected or emitted. 2. Use mirrors with detectors to measure

intensity. 3. Produce digital image of surface features.4. Examples: Landsat Image from NASA

G. Topex Poseidon Satellites1. Topex= Topographical Experiment2. Uses RADAR to detect underwater ocean features. 3. Develop maps of the ocean floor. 4. Uses remote sensing under water.

a. “Sea Beam” uses sonar to map the ocean floor.