1. Data Storage and Processing GIS Topics and Applications

2. GIS Models Over Time Simple Representation CAD model Data Analysis Raster model Data Collection Vector model Relational and Rules Object model

3. node B node C Polygon I Polygon III node A Polygon II node E node F node D Polygon V Polygon IV node G Coding Vector GIS You’ve seen this before.Let’s break it down. Vector Mode Model of Reality Reality

4. node B node C Polygon I Polygon III node A Polygon II node E node F node D Polygon V Polygon IV node G

5. node B node C Polygon I Polygon III node A Polygon II node E node F node D A topologic vector model records the points and linesshared between polygons as unique items, thus every oneof the points and lines are recorded in the data only once.

6. node B node C node A Polygon II node E node D Polygon 2 is on the right sideof the line ABCED.

7. Polygon I Polygon III node A Polygon II node E node F node D Polygon V Polygon IV Polygon 2 knows it’s adjacentto Polygons 1, 3, & 4. It shares a line segment with each. Polygon 2 knows it touchesPolygon 5. It shares node E with Polygon 5.

8. node B node C Polygon I Polygon III node A Polygon II node E node F node D Polygon V Polygon IV node G Strict Topology Features are composed from a common set of points and lines. Altering the vertices of one polygon affects polygons that share those vertices. Harder to introduce gaps or slivers.

9. Objects GIS Features as Objects is a recent method of representing aspects of the real-world in GIS Example of the shift from specialty data to DBMS that are spatially-aware Non-planar, temporally shifting, topologically linked, rule-based actions Still important to check for topology to ensure as a quality control step

10. Vector Geometry as Objects Parcels Planar geometries with attribute information Parcels as objects in a Cadastral “carpet” Objects with topology rules (“don’t overlap, unless”) Members of “regional” features (zoning, municipality) Composed of surveyed parts (COGO, benchmarks) Keys that link to attribute tables (owner(s), assessments, plans, etc)

11. Cadastre Example survey (COGO) parcels zones benchmark

12. Attributes as Objects Not only can multiple sets of geospatial features interact with rules, the attributes can be linked with one another, with their own set of rules and actions Ownership record linked to GIS parcel Search on multiple owners, records Removal of parcel warns about “orphan” owner Functions that can be performed by GIS analyst can be embedded in the actual database

13. Manipulating Vector Mode Databases

14. Common Operations Selection by Attributes or Location Dissolve Append Clip Intersect Union

15. Select by Attributes Create WHERE clauses that match a subset of the features in a vector dataset. WHERE clauses are a part of Structured Query Language (SQL) Analogous to "Find" in some other software. Match all records where… "COUNTY" = 'Gloucester' NOT "TYPE" = 'Wetlands' "POP2000" > 100000

16. Select by Location Proximity or overlay based on features in one layer and features in another layer or the same layer. Several methods to compare proximity & overlay Distance from Touching (on edge) Contains or Within Partial Overlaps Exact Matches

17. Dissolve

18. Dissolve Features Input Output

19. Append

20. Layers to Append Input Layer 1 Input Layer 2 Appended Layers Overlapping Polygons/Polylines are preserved!

21. Clip

22. Input Layer & Clipping Layer Clip Polygon Input Layer Clipped Features Output Layer

23. Intersect

24. Intersection Where are the Road segments that are in flood prone areas. Select flood prone from Input Layer 1 Intersect roads and flood prone [Layer 2].

25. Input Layer 2 Roads Intersect Features Input Layer 1 Stream Flood Prone No Flood Panel 1

26. Intersect Features Input Layer 1 Stream Flood Prone Question: where are the road segments that pass through flood prone areas? No Flood Input Layer 2 Roads Panel 1

27. Intersect Features Input Layer 1 Stream Flood Prone No Flood Select flood prone areas and then intersect Input Layer 1 with Layer 2 Roads. Input Layer 2 Roads Panel 2

28. Intersect Features Output Layer Roads Flood Prone Study Area Roads that pass through flood prone areas. Attributes of both layers maintained in table. Length of roads in flood areas becomes attribute Panel 3

29. Intersection Where are the places that are residential and flood prone? Select flood prone from Input Layer 1 Select residential from Input Layer 2 Intersect

30. Intersect Features Input Layer 1 Stream Flood Prone No Flood Panel 1

31. Intersect Features Input Layer 2 Residential Commercial Industry Panel 2 Open space

32. Intersect Features Input Layer 1 Stream Flood Prone No Flood Input Layer 2 Residential Commercial Industry Panel 3 Open space

33. Intersect Features Output Layer Residential & Flood Prone Extent Panel 4

34. Panel 2 Panel 1 Panel 3 Panel 4

35. Union

36. Panel 1 Agricultural Land Use Corn Green Beans Tomatoes Wheat

37. Panel 2 Soil Quality Poor Fair Good Excellent

38. Panel 3 Agricultural Land Use Corn Green Beans & Poor Corn &Poor Green Beans Tomatoes Corn & Excellent Green Beans & Fair Wheat Tomatoes & Fair Wheat & Excellent Soil Quality Poor Wheat & Good Fair Tomatoes & Good Good Excellent

39. Let’s See How It Works

40. Dissolve

41. 1. Right Click 2. Click to select. Dissolve Operation

42. 2. Click to open Add Field dialog 1. Click to open menu AddFieldforDissolve

43. Type a name and click OK NameandTypeofFieldforDissolve

44. Table with Code Field Resultingfield

45. Double Click Click Click DotheDissolve

46. 1 2 3 4 DissolveDialog

47. Dissolve

48. Click Double Click Click AppendOperation

49. 1 2 3 4 AppendDialog

50. Append Two layers before append One layer after append

51. Click Click Double Click ClipOperation

52. 1 2 3 ClipDialog

53. Clipping Roads before clipping Roads after Clipping

54. Intersection

55. Intersection Procedure Where are the areas that are residential in land use and flood prone? Select flood prone areas from flood prone layer Select residential areas from land use layer Do intersection

56. Intersect

57. Residential

58. SelectbyAttributesDialog Selecting flood prone and water areas

60. SelectbyAttributesDialog Selecting residential areas

63. Click Click Double Click IntersectionOperation

64. 1 2 3 4 5 6 IntersectionDialog Remember, if you did a selection, then get input features from drop down or drag into dialog from TOC

65. IntersectionResult

66. Intersection Result

67. Union

68. Click Click Double Click UnionOperation

69. 1 2 3 4 5 UnionDialog

70. This map depicts land use patterns for a portion of Washington Township prior to performing the union operation in which land use and flood prone layers were overlain. This map depicts land use patterns for a portion of Washington Township after performing the union operation in which land use and flood prone layers were overlain. Notice that some of the land use polygons have been cut creating new polygons. This occurs in areas in which a polygon from the flood prone layer intersects a land use polygon. The attributes of the new layer enable the analyst to map the coincidence of each land use category with each flood proneness category.