Finding Locations on Earth 1 Models of the Earth Finding Locations on Earth

Reference Points The points at which Earth’s axis of rotation intersect Earth’s surface are used as reference points Equator Prime Meridian

Parallels Parallels – circle that runs east and west around the Earth Parallel to equator

Latitude Latitude – angular distance north or south from equator Degrees

Latitude 360 degrees in a circle Equator to poles = ¼ of a circle ¼ of a 360 = 90 degrees 1 degree = 1/360 of earth’s circumference = 111 km’s

Minutes and Seconds 60 minutes in a degree 1 minute = 1.85 km Washington D.C. 38°53’ N 60 seconds in a minute 38°53’23”N

Longitude Meridians – semi circles that runs from pole to pole Greenwich, England – Prime Meridian Longitude – angular distance measured east or west from P.M.

½ 0f 360° = 180 0 – 180 East or West Washington D.C. 77°00’33” W

Distance between meridians vary @ poles it is less than at equator

International Date Line 180 degree Longitude Goes through Pacific ocean

Great Circles Divides globe into halves Latitude Longitude

Finding Direction Geomagnetic vs. geographic poles

Magnetic Declination Angle between the direction of geographic pole and the direction in which the compass needle points Important for map making and navigation

GPS Global Positioning System Network of 24 satellites Commercial – accurate between 10 – 15 m Military - centimeters