Transcript Latitude and Longitude PowerPoint

Longitude and Latitude
Earth is divided into imaginary lines of longitude
and latitude measured in degrees (since Earth is
spherical). These lines form Earth’s coordinate
system and enable us to locate any position on
Earth’s surface.
Directions
• Compass = tool that
uses Earth’s magnetic
field to locate magnetic
North
• Label the compass
rose with the
appropriate directions
NW
NE
W
E
SE
SW
S
Latitude
• Imaginary lines that run horizontally (east-west)
across globe
• “Ladder-tude” = look like rungs of a ladder
• Also called parallels because equal distances from
each other
• North Pole = 90⁰N Latitude (max latitude)
• South Pole = 90⁰S Latitude (max latitude)
• Equator = 0⁰ Latitude  Divides planet into
Northern and Southern Hemispheres
• Latitude in the Northern hemisphere is determined
by the altitude of the North Star, Polaris.
Lines of Latitude
Tropic of Cancer
23.5° N.
Equator
Tropic of Capricorn
23.5° S.
Finding Polaris and Ursa Minor
• To find the star Polaris and the
constellation Ursa Minor, locate
the two end stars in the cup of
the "Big Dipper."
• Connect a line through these two
stars. This will point to the star
Polaris.
• Polaris is in the constellation
Ursa Minor. Ursa Minor is better
known as the "Little Dipper."
• Polaris will not be an extremely
bright star, but it will be located
due North.
Longitude
• Imaginary lines that run vertically (northsouth) across globe
• Converge at the poles and are widest apart at
the equator
• Also called meridians
• Prime Meridian = 0⁰ Longitude – runs through
Greenwich, England
• International Date Line = 180⁰ Longitude in
Pacific Ocean (max longitude)
To find the difference in hours between
local time and Greenwich time:
• Multiply the difference by 15 per hour (The
rate at which the Earth rotates)
• If local time is earlier than Greenwich time,
then your position is West Longitude.
• If local time is later than Greenwich time, then
your position is East Longitude.
Example
1. There is a 5 hour time difference between
New York City and Greenwich, England.
What is the longitude of NYC? (Local Time in
NYC is earlier than Greenwich)
5 hrs
Step 1: What is the time difference? _______
o
5
x
15
=
75
Step 2: Multiply difference by 15⁰: _______
West
Step 3: West or East? _________
oW
75
Answer: __________
A tougher example:
2. It is 12 noon at the Prime Meridian. You are on
a boat where it is 4:00 am. You look up at the
sky and determine the altitude of Polaris to be
35°. What is your latitude and longitude?
Latitude: ALtitude of Polaris = LAtitude of observer  35oN
Longitude: 8 (time difference) x 15o = 120o W
35oN, 120oW