MAPPING THE EARTH

Maps

• A map is a two-dimensional representation of the earth.

• Maps incorporate projections and data for accuracy.

• All maps distort the earth to some extent.

• GPS has given us a much more accurate view of the surface of Earth

Most common projection is the Mercator projection - It became the standard map projection for nautical purposes because of its ability to represent lines of constant course.

Latitude & Longitude

Latitude & Longitude

0º

0º

Point of Origin

Prime Meridian

Equator

(Longitude)

(Latitude)

Latitude & Longitude

0º, 0º

Prime Meridian

Equator

10º 20º W 30º 10º 20º 30º E 10º

20º

30º

10º

20º

30º

S

N

+

Latitude

• Latitude shown by parallels (run parallel to equator)

• Show distance north/south of equator

• The equator is 0º latitude, and the north and southpoles are at 90º angles from the equator.

• The linear distance between parallel lines never changes, regardless of their position on earth. That distance is approximately 69 miles per degree anywhere on earth.

Parallels of Latitude

10º

Parallels of Latitude

10º

10º

10º

690 miles

690 miles

690 miles

10º S

0º N

10º N

20º N

Longitude • Longitude shown by meridians

• Meridians converge at the poles and are NOT parallel to each other

• The prime meridian is designated 0º and extends from the north pole to the south pole through Greenwich, England.

• The linear distance between one degree of longitude at the equator is approximately 70 statute miles.

• The linear distance between one degree of longitude at the Arctic and Antarctic Circles is

about 26 statute miles.

• One degree of longitude is equal to 60 minutes

Meridians of Longitude

10º

Meridians of Longitude

10º

10º

110º W 120º W

690 miles

460 miles

240 mi

10º

Determining Latitude & Longitude

30º N

50º W

Equator (0º)

Prime Meridian

(0º) 30ºN, 50ºW

TIME ZONES

http://www.bbc.co.uk/news/world-12849630

http://www.wisconline.com/objects/ViewObject.aspx?ID=SOC3702