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The Mercator projection (conformal cylindrical equatorial)

3 Measuring longitudes on Earth

8. Figure 3 is a view of the Earth from directly above the North Pole; the equator is the full circumference around

the edge. A line has been drawn from the North Pole to the equator and labeled 0°, representing the Prime

Meridian. Earth’s Prime Meridian through Greenwich, England, was not generally agreed to by most nations

until 1884.

a. Label the Eastern Hemisphere on the above diagram.

b. Label the Western Hemisphere on the diagram.

9. On the diagram above, draw another line from the North Pole to the other side of Earth, opposite the Prime

Meridian, and label it 180°.

a. What is the name of this line (180°)?

b. Use a protractor to measure, draw, and label the meridians that are 100° east and 60°west of the

Greenwich meridian on the above diagram.

10. Why do you think the International Date Line (on the globe) is not straight, but zigs and zags?


Time Zones

11. Write the longitude for each location and indicate if it is in the Eastern or Western Hemisphere. Then use the

time zone map (projected in the classroom, or on page 25 of your textbook to determine: If it is noon at the

following locations, what time is it in our time zone?

Location Longitude (E/W) Time in VA

Kiev, Ukraine

London, England

Los Angeles, CA

Lagos, Nigeria

Tokyo, Japan

Map Scale

Map scale is the relationship of the distances separating two points on a map to the distance separating the same two

points on the surface of the Earth, measured in the same units. Both the numerator and the denominator must be in the

same units. Scale may be expressed as a fractional scale (ratio or representative fraction), verbally, or graphically.

The denominator of a fractional scale can be difficult to visualize. A verbal scale can concert these to more

understandable units. For example, the denominator of the fractional scale 1:24,000 can be converted by dividing by 12

to get to inches, and by 63,360 to get to miles. So 24,000 inches equals 2,000 feet or .378 of a mile.

We can also set up an equation based on the equivalency statement, and then cross-multiply.