1. Objectives Vocabulary Compare and contrast latitude and longitude.
Describe how time zones vary.
Vocabulary
cartography
equator
latitude
longitude
prime meridian
International Date Line

2. Latitude and Longitude
For thousands of years, people have used maps to define borders and to find places.
Cartography is the science of mapmaking.
Cartographers use an imaginary grid of parallel lines and vertical lines to locate points on Earth.
The equator circles Earth halfway between the north and south poles separating Earth into two equal halves called the northern hemisphere and the southern hemisphere.

3. Latitude Lines of latitude are lines running parallel to the equator.
Latitude and Longitude
Latitude
Lines of latitude are lines running parallel to the equator.
Latitude is the distance in degrees north or south of the equator.

4. Latitude and Longitude
Latitude is thus measured from 0° at the equator to 90° at the poles.
Locations north of the equator are referred to by degrees north latitude (N).
Locations south of the equator are referred to by degrees south latitude (S).

5. Latitude Degrees of Latitude
Latitude and Longitude
Latitude
Degrees of Latitude
Each degree of latitude is equivalent to about 111 km on Earth’s surface.
To locate positions on Earth more precisely, cartographers break down degrees of latitude into 60 smaller units, called minutes (´).
A minute of latitude can be further divided into seconds (´´).
Longitude is also divided into degrees, minutes, and seconds.

6. Latitude and Longitude
To locate positions in east and west directions, cartographers use lines of longitude, also known as meridians.
Longitude is the distance in degrees east or west of the prime meridian.
The prime meridian, representing 0° longitude, is the reference point for longitude.

7. Latitude and Longitude
Points west of the prime meridian are numbered from 0° to 180° west longitude (W).
Points east of the prime meridian are numbered from 0° to 180° east longitude (E).

8. Longitude Semicircles Degrees of Longitude
Latitude and Longitude
Longitude
Semicircles
Lines of longitude are not parallel; they are large semicircles that extend vertically from pole to pole.
Degrees of Longitude
The distances covered by degrees of longitude vary with location.
One degree of longitude varies from about 111 km at the equator to essentially the distance covered by a point at the poles.

9. Longitude Locating Places with Coordinates
Latitude and Longitude
Longitude
Locating Places with Coordinates
Both latitude and longitude are needed to precisely locate positions on Earth.
For example, the location of New Orleans is 29°57´N, 90°04´W.
Note that latitude comes first in reference to the coordinates of a particular location.

10. Latitude and Longitude

11. Latitude and Longitude
Time Zones
Because Earth takes about 24 hours to rotate once on its axis, it is divided into 24 times zones, each representing a different hour.

12. Latitude and Longitude
Time Zones
Each time zone is 15° wide, corresponding roughly to lines of longitude.
Time zone boundaries have been adjusted in local areas for convenience.

13. Time Zones There are six different time zones in the United States.
Latitude and Longitude
Time Zones
There are six different time zones in the United States.

14. Time Zones Calendar Dates
Latitude and Longitude
Time Zones
Calendar Dates
Every time zone experiences this transition from one day to the next, with the calendar advancing to the next day at midnight.
Each time you travel through a time zone, you gain or lose time, eventually gaining or losing an entire day.
The International Date Line, or 180° meridian, serves as the transition line for calendar days.
Traveling west across the International Date Line, you would advance your calendar one day.
Traveling east, you would move your calendar back one day.

15. Latitude and Longitude
Section Assessment
1. Match the following terms with their definitions.
___ latitude
___ longitude
___ prime meridian
___ equator D B A C
A. the reference point for longitude
B. the distance in degrees east or west of 0°
C. the reference point for latitude
D. the distance in degrees north or south of 0°

16. Latitude and Longitude
Section Assessment
2. If it is 10 A.M. in Madagascar, what time is it in Washington, D.C.?
It is 2 A.M. in Washington, D.C.

17. Latitude and Longitude
Section Assessment
3. Identify whether the following statements are true or false.
_______ A degree of longitude always represents the same distance.
_______ If you travel west across the International Date Line, you advance your calendar one day.
_______ Lines of latitude are not perfectly parallel to each other.
_______ When referencing a specific place on Earth by its coordinates, latitude always comes first.
false
true

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