1. Unit 1: The World in Spatial Terms
Lesson 12: Comparing Map Projections

2. Comparing Map Projections
Why do we have maps?
Maps show us four things:
1. direction
2. distance
3. shape
4. size
Only a globe (not a map) can show ALL four, at the SAME TIME with accuracy, but it isn’t practical to carry a globe around with you
Maps are used to focus on one of the above areas
Map projections: the way we show the rounded earth on a flat piece of paper

3. Cylindrical Projection

4. Cylindrical Projections
Cylindrical Projections (Mercator): It shows what the earth would look like if a piece of paper were wrapped to form a tube or cylinder around the globe. Note: These projections distort distances and land masses near the North and South Poles.

5. Planar Projection

6. Planar Projections Planar Projections (azimuthal): -Round maps
-Look like a flattened disk of the earth’s surface
-Longitude lines (those running up and down; north/south) are straight and meet in the center
-Latitude lines (those running horizontal; east/west) form circles that get smaller as they get closer to the center
-Usually used to look at the North and South Pole

7. Conic Projections

8. Conic Projections
Good for showing small areas midway between the Equator and the Poles
Latitude lines are curved
Longitude lines get closer together toward the north, or top of the map
Size, distance and direction are fairly accurate

9. Other Map Projections
Robinson-shows size, distance and shape of land masses with only minor distortions

10. Other Map Projections
Goode-shows the shape and size of land masses with a high degree of accurately

11. Winkel Tripel Projection
Most commonly used general reference map
Balances size and shape of land areas, even polar areas show very little distortion