Aim: How do we locate positions on Earth? I. Coordinate System – assigns to every position on Earth a pair of coordinates (2 numbers) called latitude and longitude. A. Latitude – is the distance in degrees north and south of the equator. 1. Parallels – imaginary lines that circle the world from east to west parallel to the equator.

THE LATITUDE STORY "Give me some latitude, Lulu! What's it all about!" "Hmmmn! Well, let's look at it this way... Think of the earth as a ball or a sphere, spinning about an imaginary axis. In the drawing I've made, the ends of the axis are labeled N for North Pole and S for South Pole!" "Imagine that 180 equally spaced, parallel circles are painted on the earth. The N-S axis of the earth runs right through the center of each circle. The further the circles are from the poles, the larger they are. The two circles that are right at the poles are so small they are actually just points. All these circles are called PARALLELS or LINES OF LATITUDE!"

2.Common Latitudes: a.Equator – 0 o b.North Pole - 90 o N c.South Pole – 90 o S 3. 1 degree of latitude = 112 km (70 miles) 4. 1 degree of latitude = 60 minutes (60’) = 1.85 km or 1.16 miles.

B. Longitude – is the distance in degrees east or west of the Prime Meridian 1. Meridian –half circle that runs in a north- south direction from the north pole to the south pole. 2. Prime Meridian – Starting point for worldwide longitude system. Passes through Greenwich, England. 3. Longitude of Prime Meridian is 0 o 4. If you move east or west around the Prime Meridian, the furthest longitude value is (half circle)

5. International Date Line – 180 th Meridian

units/mapping/latitude.cfm