Latitude&

Longitude

Latitude Longitudeline running east to westmeasures the distance in degrees North and South of the equator.-measured by parallels, because all lines of latitude are parallel.-largest value of latitude is 90°

- Equator – 0°00’ N/S

- North Pole – 90°00’ N

- South Pole – 90°00’ S

- Horseheads, NY – 42°10’N

-line running north to south-measures the distance in degrees East and West

of the prime meridian.-All meridian lines meet at the poles and are further apart at the equator. They are not parallel-largest value of longitude is 180° -Prime Meridian – 0°00’ E/W Horseheads, NY – 76°51’ W

Latitude

49o

Latitude lines are also called PARALLELS because they run parallel to the equator.

Latitude• At night in the Northern

Hemisphere, latitude can be determined by measuring the altitude of Polaris (North Star)

40o

North Pole

To Polaris

Horizon

90°

To Polaris

40°To Polaris

0°

Longitude• Based on the Sun’s Apparent motion through

the sky.• How long does it take the Earth to rotate once

on its axis?» 24 hours

• How many degrees does it rotate in this time?» 360o

• Degrees per hour = 360/24 = 15o/hour

Longitude

• The distance, in degrees, measured east or west of the Prime Meridian.

• Prime Meridian passes through Greenwich, England (Longitude 0o)

Measuring Longitude

• Greenwich Mean Time (GMT) – what time it is in Greenwich, England– 0o line for longitude

• Solar Time – (noon) – when the sun reaches it highest altitude in the

sky at your location.

Measuring Longitude

• Remember – the Earth rotates at 15o/hr and that the Sun “appears” to move through the sky at the same rate.

• If you know what time it is in Greenwich when it is noon at your location you can calculate you longitude.

Measuring Longitude• It was 2:00 pm in

Greenwich (GMT) when it was noon at your location (12:00pm)

• Time Difference =? 2 hours• 2 hours X 15o/hr

= 30o

• Your longitude = 30oW

Note – If it is NOON your time and GMT = PM, you are WEST of the P.M.

If it is NOON your time and GMT = AM, you are EAST of the P.M.

Earth Rotates from W to E

Longitude and Time

Longitude and Time

South

Nor

th

Writing Latitude & Longitude

• Latitude (N or S) comes FIRST, followed by the longitude (E or W)

45o N, 33o E85o S, 123o W

95o S, 47o E Anything WRONG here!!

• Latitude and Longitude are measure in DEGREES AND MINUTES

Xo Y ‘ Degrees Minutes

There are 60 minutes in one degree

Examples: Latitude 30o45’ N Longitude 46o12’ E