1. Map Projections GIS-101 Summer 2006 Semester

2. Important Things to Remember about Map Projections An attempt to take location information from a spheriod object and transfer to a flat surface As such, ALL projections are a distortion of the real world to some extent!

3. Attributes of Distortion Shape Size Distance Direction Area

4. Map Projections versus Coordinate Systems REMEMBER: Map Projections and Coordinate Systems are two different things!

5. Factors Associated with Map Projections Scale Map Units Projection Coordinate System Datum

7. Map Scale vs Spatial Scale 1:24,000 is a LARGER scale than 1:100,000 e.g. 1/24,000 is a larger number than 1/100,000 However, 1:24,000 however covers a smaller spatial scale than 1:100,000 (i.e. less area covered on a same sized map)

8. Topographic Mapping System

9. Examples of Projections Robinson Lambert Conformal Conic Mercator Transverse Mercator

10. Types or “Families” of Map Projections Cylindrical Conic Azimuthal or Planar

12. Orthographic Projection

14. Lambert Conformal Conic

15. Azimuthal Projection

16. Transverse Mercator

17. Mercator Projection

19. Examples of Coordinate Systems Latitude and Longitude (Geographic) Universal Transverse Mercator State Plane

20. Geographic Coordinate System Latitude & Longitude NOT a true “Projection”

21. Latitude / Longitude for US

26. UTM Grid Uses Transverse Mercator projection Units usually in meters 60 Zones 6 degrees per zone “N” or “S” Example:

27. UTM Coordinate System (US)

28. UTM Coordinate System

29. State Plane Uses either Lambert Conformal Conic (East- West States) OR Transverse Mercator (North-South States) Projections Units usually in feet

30. State Plane Coordinate System

31. Township & Range System