Class 3a:  The Round Earth, or Map Projections and Climate Basics
How hot is it? <ul><li>What determines temperature? </li></ul><ul><li>Insolation ( in coming  so lar radi ation ) </li></u...
Insolation <ul><li>Only at one latitude at a time are the sun’s rays overhead </li></ul><ul><ul><li>Between Tropic of Canc...
What causes the seasons? <ul><li>Volunteers? </li></ul><ul><li>The tilt of the earth </li></ul><ul><li>The angle of sunlig...
 
Latitude and longitude <ul><li>Latitude: how far north or south </li></ul><ul><li>From 0° at equator to 90° at poles </li>...
Latitude and longitude <ul><li>Longitude: how far east or west </li></ul><ul><li>East or west of what? </li></ul><ul><li>1...
 
 
Map projections <ul><li>Project a round globe onto a flat surface </li></ul><ul><li>Options? </li></ul><ul><li>Stretch out...
Map projections <ul><li>Three properties to consider </li></ul><ul><ul><li>Area (equal-area or equivalent) </li></ul></ul>...
Cylindrical projections <ul><li>Shapes are preserved </li></ul><ul><li>But not area! </li></ul><ul><li>Mercator projection...
Cylindrical projections: Gall- Peters <ul><li>Adjusting Mercator for a more “just” map  </li></ul><ul><li>Also preserves a...
Conic projections <ul><li>Best for hemispheres or small regions </li></ul><ul><li>Area and shape only slightly distorted <...
Planar projections <ul><li>Equidistant; good for navigation </li></ul><ul><li>Only good for one hemisphere </li></ul><ul><...
Other projections <ul><li>Based on more complicated math </li></ul><ul><li>Interrupted, oval, combination </li></ul>Goode ...
 
Dymaxion
 
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Maps

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Maps

  1. 1. Class 3a: The Round Earth, or Map Projections and Climate Basics
  2. 2. How hot is it? <ul><li>What determines temperature? </li></ul><ul><li>Insolation ( in coming so lar radi ation ) </li></ul><ul><li>Cloud cover </li></ul><ul><li>Altitude </li></ul><ul><li>Water vapor in the air </li></ul><ul><li>Land or water </li></ul><ul><li>Air movement (wind) </li></ul>
  3. 3. Insolation <ul><li>Only at one latitude at a time are the sun’s rays overhead </li></ul><ul><ul><li>Between Tropic of Cancer and Tropic of Capricorn </li></ul></ul><ul><li>Everywhere else, rays are diffused </li></ul>
  4. 4. What causes the seasons? <ul><li>Volunteers? </li></ul><ul><li>The tilt of the earth </li></ul><ul><li>The angle of sunlight </li></ul><ul><li>The change in heat received from the sun </li></ul>
  5. 6. Latitude and longitude <ul><li>Latitude: how far north or south </li></ul><ul><li>From 0° at equator to 90° at poles </li></ul><ul><li>Each parallel of latitude is a different size </li></ul><ul><li>Key latitudes: Equator, 23.5°N and S </li></ul>
  6. 7. Latitude and longitude <ul><li>Longitude: how far east or west </li></ul><ul><li>East or west of what? </li></ul><ul><li>1884 agreement on prime meridian at Greenwich </li></ul><ul><li>Each meridian of longitude is the same distance around </li></ul><ul><li>Not parallel lines </li></ul><ul><li>Key longitudes: Prime Meridian, International Date Line, 100 th meridian </li></ul>
  7. 10. Map projections <ul><li>Project a round globe onto a flat surface </li></ul><ul><li>Options? </li></ul><ul><li>Stretch out some areas </li></ul><ul><li>Cut out some areas </li></ul><ul><li>Shrink some areas </li></ul>
  8. 11. Map projections <ul><li>Three properties to consider </li></ul><ul><ul><li>Area (equal-area or equivalent) </li></ul></ul><ul><ul><li>Shape (conformal) </li></ul></ul><ul><ul><li>Distance (equidistant) </li></ul></ul><ul><ul><li>Choose two out of three </li></ul></ul><ul><li>How large an area? </li></ul><ul><li>Purpose of the map </li></ul><ul><li>Ulterior motives? </li></ul>
  9. 12. Cylindrical projections <ul><li>Shapes are preserved </li></ul><ul><li>But not area! </li></ul><ul><li>Mercator projection </li></ul><ul><li>Deliberate distortion? </li></ul><ul><ul><li>Cold War </li></ul></ul><ul><ul><li>Colonialism </li></ul></ul>
  10. 13. Cylindrical projections: Gall- Peters <ul><li>Adjusting Mercator for a more “just” map </li></ul><ul><li>Also preserves area </li></ul><ul><li>Distorts shape differently </li></ul>
  11. 14. Conic projections <ul><li>Best for hemispheres or small regions </li></ul><ul><li>Area and shape only slightly distorted </li></ul>
  12. 15. Planar projections <ul><li>Equidistant; good for navigation </li></ul><ul><li>Only good for one hemisphere </li></ul><ul><li>Distorts area, not shape </li></ul>
  13. 16. Other projections <ul><li>Based on more complicated math </li></ul><ul><li>Interrupted, oval, combination </li></ul>Goode Robinson
  14. 18. Dymaxion
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