Objectives• Compare and contrast latitude and longitude.

Latitude and Longitude

• Describe how time zones vary.

– cartography

– equator

– latitude

– longitude

– prime meridian

– International Date Line

Vocabulary

• 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.

• Cartography is the science of mapmaking.

Latitude and Longitude• For thousands of years, people have used maps

to define borders and to find places.

Latitude and Longitude

Latitude• Lines of latitude are lines running parallel to

the equator.

Latitude and Longitude

• Latitude is the distance in degrees north or south of the equator.

Latitude• Latitude is thus measured from 0° at the equator

to 90° at the poles.

Latitude and Longitude

• 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).

Latitude

Degrees of Latitude

Latitude and Longitude

– 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.

Longitude• To locate positions in east and west directions,

cartographers use lines of longitude, also known as meridians.

Latitude and Longitude

• 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.

Longitude• Points west of the prime meridian are numbered

from 0° to 180° west longitude (W).

Latitude and Longitude

• Points east of the prime meridian are numbered from 0° to 180° east longitude (E).

Longitude

Semicircles

Latitude and Longitude

– Lines of longitude are not parallel; they are large semicircles that extend vertically from pole to pole.

– 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.

Degrees of Longitude

Longitude

Locating Places with Coordinates

Latitude and Longitude

– 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.

Latitude and Longitude

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.

Latitude and Longitude

Time Zones• Each time zone is 15° wide, corresponding

roughly to lines of longitude.

Latitude and Longitude

• Time zone boundaries have been adjusted in local areas for convenience.

Time Zones• There are six

different time zones in the United States.

Latitude and Longitude

Time Zones

Calendar Dates

Latitude and Longitude

– 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.

Section Assessment

1. Match the following terms with their definitions.

___ latitude

___ longitude

___ prime meridian

___ equator

Latitude and Longitude

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°

D

B

A

C

Section Assessment

2. If it is 10 A.M. in Madagascar, what time is it in Washington, D.C.?

Latitude and Longitude

It is 2 A.M. in Washington, D.C.

_______ 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.

Section Assessment

3. Identify whether the following statements are true or false.

Latitude and Longitude

false

true

false

true

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