Transcript Locating Positions on the Earth’s Surface

Locating Positions on the
Earth’s Surface
Coordinate System
• Surface grid used to locate any position on
the Earth
• Latitude and Longitude
System uses two reference points:
1. Equator – (00 latitude)
• Imaginary line that circles the earth
• The angular distance north or south of the
equator is called latitude
• Lines of latitude are parallel to each other
2. Prime Meridian (00 longitude)
• Runs from the north pole to the south pole
through Greenwich, England
• The angular distance east or west of the Prime
Meridian is called longitude.
• Longitude lines meet at the poles and run
north to south
Lines of latitude and longitude on
the Globe
P
R
I
M
E
M
Equator--
E
R
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D
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A
N
Globe
Globe to Mercator
Notice the distortion in the polar
regions.
South America is
actually 9 times the
size of Greenland
An area of the world will always be
distorted with these projections.
Projections
Projections
Map Projections.asf
Distance using Latitude
• One degree of latitude = 111km
• Each degree is divided into 60 minutes
(60’) Each minute = 1.85km
• Each minute is divided into 60 seconds
(60”)
– 420 30’ 15” N is read as 42 degrees, 30
minutes and 15 seconds north
– This means the location is 4718km north of
the equator
Distance using Longitude
• At the equator, one degree of longitude =
111km
• As you go towards the poles, this distance
decreases