1. MAP PROJECTIONS I. Creating a Map Projection II. Classifying Projections III. Putting Map Projections to Use

3. Tissot Indicatrix

5. Scale Factor Scale Factor = actual scale/nominal scale SF = 1.0 would indicate the scale on the projection is the same as the globe. SF = 2.0 would indicate the scale on the projection is two times as large as the globe. SF = 0.75 projection scale is 25% smaller than the globe. The scale factor on any map is going to vary from point to point. No map has a uniform scale.

6. BASIC PROJECTIONS l There are three basic projections that are grouped into families: planarconic Cylindrical (pseudocylindric)

7. TangentSecant

8. TangentSecant

9. TangentSecant

10. TRANSVERSE OBLIQUE POLAR OBLIQUE

11. PRESERVED PROPERTIES OF MAP PROJECTIONS DISTANCE (equidistant projections) SHAPE (conformal projections) DIRECTION (azimuthal projections) AREA (equivalent projections)

12. USE OF MAP PROJECTIONS WORLD PROJECTIONS lEquivalency is the overriding concern. Three accepted equal area projections: –Mollweide –Hammer –Boggs

13. MOLLEWEIDE world thematic distributions

14. HAMMER world distribution

15. BOGGS greater shape preservation at equator

16. ROBINSON best at equal-area

17. USE OF MAP PROJECTIONS CONTINENTS l In this case you are looking for either equivalence or conformality. l Bonne projection is commonly used to map continents on either side of the equator.

18. Bonne

19. USE OF MAP PROJECTIONS Large & Small Countries at Mid-Latitudes l Most commonly used: l Bonne l Lambert equal area azimuthal l Albers equal area

20. OBLIQUELAMBERT EQ. AREA AZIMUTHAL

21. ALBERS EQUAL AREA

22. USE OF MAP PROJECTIONS LOW LATITUDES lThe following projections can be used along equatorial regions. –Mollweide –Hammer –Sinusoidal

23. MOLLEWEIDE

24. HAMMER

25. SINUSOIDAL

26. USE OF MAP PROJECTIONS STATES IN THE UNITED STATES l The three conformal projections: l Lambert conformal conic--states with a long east-west dimensions (Tenn.) l Transverse Mercator--states with long north-south dimensions (Ca. or Fla.) l Oblique Mercator--generally used in Alaska

27. Lambert Conformal Conic

28. Transverse Mercator

29. OBLIQUE MERCATOR