1. GIS Lecture: Geoprocessing

2. Outline
Geoprocessing Tools
Model Builder

3. Geoprocessing Tools

4. Geoprocessing Tools GIS operation to manipulate data
Take input data sets, manipulate, and produce output data sets
Often use multiple data sets

5. Common geoprocessing tools
Analysis
Proximity - Buffer
Extract – Clip
Overlay – Intersect and Union
Data management
Generalization – Dissolve
General
Append
Merge

6. Accessing tools
Geoprocessing menu

7. Accessing tools
ArcToolbox

8. Accessing tools
Search window

9. Proximity Buffers

10. Point Proximity Buffers
Point buffers are circular with a user-supplied radius

11. Point buffer example
Drug-free zones: criminal penalties are higher for drug dealing within 1,000 feet of a school

12. Point buffer example Polluting company buffers Added schools
Added population
Data from U.S. Census and EPA website

13. Line Proximity Buffers
Line buffers look like a worm

14. Line buffer example
Businesses within 0.25 miles of a selected street being paved

15. Select features in buffer

16. Polygon Proximity Buffers
Polygon buffers extend polygons outward and round-off corners

17. Polygon buffer example
Parcels within 150′ of selected property
Need to send notifications to adjacent land owners about a requested zoning variance at selected property (commercial land use in residential area)

18. Select features in buffer

19. Spatial Joins With Buffers
- Spatially join toxic release sites to buffers
- Count appears in new buffer

20. Multiple ring buffer
Each distance produces a separate polygon.

21. Clip Features

22. Clip
Uses “cookie cutter” to select features
Input
Clip Feature
Output

23. Line (Arc) Clipping Input layer: Streets Clip layer:
Central Business District (selected neighborhood)
Output layer:
Clipped Streets
(within Central Business District only)

24. Difference Between Clipping and Select by Location
Clip: Clean “cut”
Select by Location Intersect: Dangle edges

25. Dissolve Features

26. Dissolve combines adjacent polygons to create new, larger polygons
uses common field value to remove interior lines within each polygon, forming new polygons
can also aggregate (sum) data while dissolving
Input
Output

27. Dissolve Create regions using US states
Use SUB_REGION field to dissolve
Sum population

28. Dissolve

29. Dissolve results States dissolved to form regions
Population summed for each region

30. Append Features

31. Append Appends one or more datasets into an existing dataset
features must be of the same feature type
input datasets may overlap one another and/or the target dataset
TEST option: fields must be the same and in the same order
NO TEST option: fields do not have to match

32. Append Streets
DuPage and Cook County are combining public works and need a new single street centerline file.

33. Append Streets
Append will add DuPage to Cook County streets

34. Resultant Layer
One street layer with all records and field items

35. Union Features

36. Union Overlays two polygon layers
Resulting output layer has combined attribute data of the two inputs
Contains all the polygons from the inputs, whether or not they overlap

37. Union
Start with ZIP codes and Neighborhoods

38. Union
Attributes tables contain different data

39. Union
Union neighborhoods and ZIP Codes to include the zip on each neighborhood polygon

40. Resultant Layer
Polygons are combined with both attribute tables

41. Intersect Features

42. Intersect Computes a geometric intersection of the input features
Features or portions of features which overlap in all layers

43. Intersect
City manager needs to know what buildings intersect flood zones and wants the flood data attached to each intersecting building

44. Intersect

45. Intersect result
Only building polygons that intersect flood zones with combined data fields

46. Model Builder

47. Model Builder Workflow processes can be complicated
Models automate and string tools together
You run a model with one click of a button

48. Add Functions to Model
Drag and drop layers from Table of Contents and functions from ArcToolbox

49. Model Builder Example
Run the model…

50. Model Builder Examples

51. Model Builder Examples
Simple to Complex

52. Summary
Geoprocessing Tools
Model Builder