Map Projections

Map Projections Putting a sphere on a flat surface messes up certain realities: Distance Direction Shape Area Each map keeps one or two things true (pros), but the others are not accurate (cons).

Mercator Pros: Direction Cons: Shape Distance Area Africa is actually 14 times larger than Greenland!

Robinson Pros: Cons: Better area Direction and shape Distance

Goode homolosine Pros: Shape Area Cons: Direction Distance

Latitude and Longitude

Hemispheres

Hemispheres

The Earth’s Grid Any spot on Earth can be plotted with latitude and longitude. Lines of latitude run east-west “Lateral” means “side-to-side” (lateral pass) Also called parallels Measured in degrees of N or S 0° latitude is the Equator 90° N is the North Pole 90° S is the South Pole

Latitude Measure North Equator Measure South

Upper Latitudes Lower Latitudes

Longitude Lines of longitude run north-south “All lines of longitude are long” Also called meridians Measured in degrees of E or W 0° longitude is the Prime Meridian Runs through Greenwich, England, just outside London 180° E/W is the International Date Line

Longitude 180° W 180° E 0° Measure West Prime Meridian Measure East

35º N 34º 5’ N 34º N 18º E 19º E 18º 25’ E

The Earth’s Grid A specific location uses N or S and W or E for each coordinate pair Three ways to show coordinates: Degrees, minutes, seconds: 30°, 15’, 45” N; 54°, 20’, 10” W 1 degree = 60 minutes; 1 minute = 60 seconds **Note: This is not in reference to time! Deg:min:sec : 30:15:45N, 54:20:10W

Three ways to show coordinates continued: 30:15:45N, 54:20:10W = Decimals: 30.2625, -54. 336111 ** (south and west are negative numbers) Found by dividing minutes/60 i.e. 15 minutes = 15/60 = .25 And then seconds/3600 i.e. 45 seconds = 45/3600 = .0125 Add the two together: .25 + .0125 = .2625

Latitude and Longitude Together, any point on Earth can be plotted on a map Use both coordinates together: Latitude, longitude 40° N, 85° E 10° S, 15° W Walton: 33:59:20.663 N, 84:26:30.718 W This is the Front Office

Why Degrees, Minutes, Seconds? A circle is 360° When computing various angles, we base our measurements on degrees. i.e. Right angles are 90 ° An angle between 90° and 91° require requires minutes and seconds to find the specific angle. In 3D, we add the Z Axis, which requires the second degree measurement