locating positions on the earth’s surface
DESCRIPTION
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:. Equator – (0 0 latitude) Imaginary line that circles the earth - PowerPoint PPT PresentationTRANSCRIPT
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 other2. 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
Equator--
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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