WEEK THREE

1. WEEK THREE

2. Map of the Day • Data: Terrorist Plots AND Drone Strike Locations in Yemen • Goal: 1 map that shows both • 2000-2012 • What does your map look like?

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 BrewerQualitative or Quantitative?

13. Qualitative or Quantitative?

14. Why Does This Matter?

15. Qualitative or Quantitative?

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/ContinuousAbrupt/Smooth • Who cares??

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