1. Mapping

2. Maps
Maps can depict visible surface features (towns), underground features (subways), and abstract features (political boundaries)
Not possible to accurately represent round Earth on flat surface
Spatial concepts on maps—distance, direction, density, diffusion, linkage, flow, arrangement, accessibility

3. Latitude
Equator marks the zero degree parallel and is fixed by the laws of nature
Sailors measured latitude by length of day, height of sun, or known guide stars
Angle measured north or south from equator from 0° to 90°
Chicago--42° N

4. Longitude
Prime Meridian location is a political decision—Royal Observatory at Greenwich, England
Longitude measured by time—each hour’s time difference between ship and home port indicated 15 degrees
Intersect parallels at right angles
Measured east or west 0° to 180°
New York City--74° W

5. Minutes and Degrees Basic latitude/longitude is degree
Each degree is divided into 60 minutes
Each minute is divided into 60 seconds
For more precision on a location, specify minutes or even seconds
Sometimes degrees are written as decimals (36º N)

6. Map Scale
Relationship between distance on the map and distance on the ground
Usually written as a fraction or ratio
1:10,000 or 1/10,000 (1 inch of measurement on the map equals 10,000 of same units on ground)

7. Map Scales (from USGS.com)
1 to 24,000 scale
1 to 250,000 scale
1 to 100,000 scale

8. Orientation Never Eat Soggy Waffles
North, East, South, West
Can use clock for directional reference
“Dolphins at 1:00”

9. Good Map Elements (DOGSTAILS)
Date—when map was made
Orientation—directions
Grid—locates places on map
Scale—map distance
Title—what, where, when
Author—who made map
Index—map address of places
Legend—what the symbols mean
Sources—basis for map information

10. Map Types Reference Thematic Political Physical Topographic Satellite
Choropleth
Cartograms

11. Map Problems
When the National Geographic Society came out with it’s sixth Atlas edition, it contained approximately 10,000 changes, and was already out of date when it went for sale
Countries argue over names
Korea: East Sea
Japan: Sea of Japan

12. Why Maps Lie Cartographers are not licensed Maps distort reality
Single map is one of large number of maps that could be produced from same data
Flat map stretches some distances and shortens others
Simplification
Generalization

13. Common Map Errors Based on incompatible sources Misspelled place-names
Graytone symbols changed by poor printing
Compiled from other maps
Map drafters having fun and including fictitious towns
International data based on inconsistent definitions

14. Globe v. Map
Peel an orange into four equal pieces and lay the pieces side by side on a flat surface. Observe how the landmasses fit together.

15. Why we have different maps
Distortion exists with flat maps so cartographers use different projections to preserve selected properties (shape, size, distance, direction)

16. Map Projections Mercator Projection
Good for navigation at sea because of straight lat/long lines
Renders Greenland as large as South America (yet 1/8 of size)
Flemish cartographer (1500s)

17. Map Projections Robinson Projection
Accurate depiction of continent’s sizes and shapes
Distortion greatest at poles

18. Map Projection J. Paul Goode (1923) Homolosine Equal-Area Projection
Less distorted land masses by giving up continuous oceans

19. Map Projection
Conic
Best for showing one section of Earth without much distortion

20. Map Projection Polar Used mostly to show one hemisphere at a time
Accurate for distance
and direction