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On Some Fundamental Geographical Concepts

On Some Fundamental Geographical Concepts. 176B Lecture 3. Nystuen, J. D. (1963) “Identification of some fundamental spatial concepts”. Search for a common geographical terminology to eliminate redundancy Basics: Distance, pattern, relative position, site and accessibility

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On Some Fundamental Geographical Concepts

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  1. On Some Fundamental Geographical Concepts 176B Lecture 3

  2. Nystuen, J. D. (1963) “Identification of some fundamental spatial concepts” • Search for a common geographical terminology to eliminate redundancy • Basics: Distance, pattern, relative position, site and accessibility • Advantages of abstract models and assumptions, e.g. isotropic surface

  3. The mosque floor

  4. Geographic primitives • G = g (x, y, z, s, A, t) • [x, y, z] = f(l, f, d) • Geography also highly dependent upon model

  5. UCSBLat: 34.4087 Lon: -119.8447

  6. Projection, datum etc. for a 7.5 min quad

  7. GIS basic geometric functions • A GIS package must be able to move between • map projections • coordinate systems • datums • Ellipsoids • A GIS must be able to GEORECTIFY • Not always a simple task!

  8. Orthorectification

  9. Georegistration: Control

  10. Georectification

  11. Conflation

  12. Address matching 2123 South Main St. Anywhere CA 93901 4,312,205mN 623,864mE 15N

  13. Geographic information fundamentals • Volume • Dimensionality • Continuity

  14. Volume • 1 meter pixel • 24 bit depth (8 bit R, 8 bit G, 8 bit B) • California 3rd largest State A=158,706 square miles • A= 411,046,653,039 square meters • N=9.865x10^10 bytes • 98 gigabyte image

  15. Volume Issues: Tiles and Pyramids

  16. Dimensionality • Simple geographic features can be used to build more complex ones. • Areas are made up of lines which are made up of points represented by their coordinates. • Areas = {Lines} = {Points}

  17. Areas are lines are points are coordinates

  18. Continuity • Attributes of the earth fall into different spatial “behaviors” over space and time • Many phenomena are best treated as continuous fields • E.g. air temperature, atmospheric pressure, population density • Others have distinct spatial extent or edges • E.g. census tracts, buildings, roads

  19. Field vs. Feature (object)

  20. Fields are often rasters

  21. Air Photos 1929 Discontinuous irregular rasters: resampling

  22. Features are often vectors

  23. Properties of Features • Size • Distribution/density • Shape • Scale • Orientation

  24. Size: Resolution and Extent 10cm, 25cm, 50cm, 1m

  25. Resels: Non-uniform Support

  26. Data structure conversion

  27. Distribution

  28. Geographical Clustering

  29. Clusters on points/networks

  30. Shape

  31. Shape vs. Support

  32. Shape measures/analysis

  33. Scale: RF vs. Detail Santa Barbara

  34. Scaling behavior

  35. Orientation: Objects & Frame

  36. Tobler’s First Law of Geography • “Everything is related to everything else but near things are more related than distant things” (Tobler, 1970) • Variation of (x1 – x0)2 • Spatial autocorrelation • Violates assumptions of statistics

  37. Geographical relations • Among features • Contains/overlaps/intersects • Contiguity/Adjacency • Proximity • Trajectory • Within fields • Neighborhood relation • Pattern • Process

  38. Vector polygon overlay = O

  39. Raster overlay 0 1 = &

  40. Buffering

  41. Pattern

  42. Pattern (Fourier) Analysis

  43. Contiguity http://www.clearproject.net/chapter10fig5.JPG (Clear Lake, Iowa)

  44. Semivariogram

  45. Most important, process… • G = g (x, y, z, s, A, t) t0 t1 t2 t3

  46. Strands

  47. Time-Space dynamics

  48. 1930 1950 1970 1980 1990 TO FROM Dynamics

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