1. WEEK THREE

2. Map of the Day
Data: Terrorist Plots AND Drone Strike Locations in Yemen
Goal: 1 map that shows both
What does your map look like?

3. This interactive map illustrates the two critical elements of the war in Yemen: the red dots represent 71 known U.S. drone, missile or other air strikes carried out since 2002, and the blue dots show 19 major terror plots against Western targets believed to be directed by Al Qaeda or AQAP since 2000.

5. Principles of Symbolization
EMR 21
September 19, 2012
Chapter 5 / Slocum Text

6. What’s the point? The Basic Principles of Symbolizing Phenomena
The Congruence Principle
Lots of ways to think about and differentiate geographic phenomena
Different kinds of phenomena need different kinds of maps

7. Diagnose your data
Different data require different visual treatments

8. Diagnose your data Different data require different visual treatments
Build a visual structure that mimics the nature of your data’s structure
Qualitative vs. Quantitative / Discrete vs. Continuous / Abrupt vs. Smooth
Points, Lines, Polygons, Volumes
Levels of Measurement
Visual Variables

9. The thematic map
Also called the “statistical map,” “single-topic map,” or the “special-purpose” map
Less literal than a general-reference map
Two groups of thematic maps: qualitative and quantitative

10. The 2 kinds of thematic maps
Qualitative thematic maps
Show the spatial distribution or location of kind
Land use
Soil types
Languages
Restaurants
These maps are concerned with kinds, names, types (nominal data)

11. The 2 kinds of thematic maps
Quantitative thematic maps
Spatial aspects of numerical data
Corn yield
Per Capita Income
Number of Tornadoes
Population Density
These maps are concerned with amounts, or quantities
Can you tell the difference?
Is the attribute a quantity or a quality?

12. This here is a Thematic map: Lung cancer in white males, by Brewer Qualitative or Quantitative?

13. Qualitative or Quantitative?

14. Why Does This Matter?

15. Qualitative or Quantitative?

17. Mimic the sequence in the data with sequence in the symbology

18. Geographic Phenomena The things we want to map
5 geometric models of geographic phenomena
Differentiated by spatial dimensions

19. Spatial Arrangement of Data
5 types of geographic phenomena
differentiated by spatial dimensions
Zero-dimensional – ?
One-dimensional - ?
Two-dimensional - ?

20. Spatial Arrangement of Data
5 types of geographic phenomena
Separated by spatial dimensions
Zero-dimensional – points
One-dimensional - lines
Two-dimensional – areas
2.5-dimensional - ?
Three-dimensional - ?

21. Point Phenomena
Points have no spatial-extent: zero-dimensional

22. Point Phenomena Points have no spatial-extent: zero-dimensional
Examples of geographic point data?

23. Point Phenomena Points have no spatial-extent: zero-dimensional
Examples of geographic point data?
Weather stations, oil wells, eagle nesting sites
Location described by coordinates
(X,Y)
(X,Y,Z)

26. Linear Phenomena Lines have 1 dimension: length, but no width
Examples of geographic lines?

27. Linear Phenomena Lines have 1 dimension: length, but no width
Examples of geographic lines?
Borders between countries
Flight lines

28. Linear Phenomena Lines have 1 dimension: length, but no width
Examples of geographic lines?
Borders between countries
Flight lines
Described by a series of coordinate locations

31. Areal Data 2-dimensional in spatial extent: length and width
Examples of geographic areas?

32. Areal Data 2-dimensional in spatial extent: length and width
Examples of geographic areas?
Lakes, political areas…
Described using a series of coordinates that close a region

34. Volumetric Phenomena
2.5-Dimensional Phenomena
3-Dimensional Phenomena

35. Volumetric Phenomena 2.5-Dimensional Phenomena
1 x value, 1 y value, 1 z value
Every x,y pair has a single value associated with it
“A surface” – example: elevation
3-Dimensional Phenomena

36. Volumetric Phenomena 2.5-Dimensional Phenomena
1 x value, 1 y value, 1 z value
Every x,y pair has a single value associated with it
“A surface” – example: elevation
3-Dimensional Phenomena
True 3-D data are multivalued
Each x,y pair can have many z values

37. True 3-D phenomena 4 important values X-value Y-value
Z-value (height above or below)

38. True 3-D phenomena 4 important values X-value Y-value
Z-value (height above or below)
Measured value of Phenomenon

39. True 3-D phenomena 4 important values X-value Y-value
Z-value (height above or below)
Measured value of Phenomenon
The first 3 are locational coordinates, the last describes the attribute
EXAMPLES?

40. How does map scale influence spatial dimension?
Map Scale and cities?
Map Scale and rivers?
Models of geographic phenomena
Reducing geographic realities to geometric primitives

41. Other phenomenal characteristics
Discrete v. Continuous
Abrupt v. Smooth

42. Discrete Phenomena Occur at distinct location With space in between
Examples: people living in a city – as points, space between
Weather stations
Restaurants

43. Continuous Phenomena Continuous phenomena are defined everywhere:
Examples: elevation, air pressure, temperature, land cover

44. How do they change? Phenomenon can change two main ways over space…
Abruptly or Smoothly

45. What things change abruptly?

46. What things change abruptly?
Tax rates
Spending on public school students
Number of postal employees
# of electoral votes

47. What things change smoothly?

48. What things change smoothly?
Precipitation levels
Influenza cases
See figure 4.1 in your book.

49. Discrete/Continuous Abrupt/Smooth
Who cares??

50. Ratio of Unmarried Men to Unmarried Women in US (Census)
Who cares??

52. Terrorist Plots and Drone Strikes in Yemen 2000-2012
Who cares??

54. NBA Field Goal Percentage
Who cares??