Transcript Map Projections Latitude & Longitude Map Scales

Latitude
&
Longitude
Latitude
line
running east to west
measures 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
Longitude
-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
To Polaris
To Polaris
90°
40°
To Polaris
0°
Horizon
North
Pole
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 –
  Earth Rotates from W to E  
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.
Longitude and Time
Longitude and Time
N
o
r
t
h
S
o
u
t
h
Writing Latitude & Longitude
• Latitude (N or S) comes FIRST, followed by the
longitude (E or W)
45o N, 33o E
85o 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