Embed Size (px)
Citation preview
1. Data Quality for GIS
2. GIS quality-related issues
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 1
3. Data Quality
4. GIS Projects – Cost versus Accuracy: Hypothetical Exam...
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 2
5. Request to develop land use layer for Texas town
6. Data Quality Concepts
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 3
7. Accuracy, precision, resolution
8. Types of accuracy requirements
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 4
9. Types of error
10. Positional error
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 5
11. Source of the “true value” for estimating accura...
12. US National Map Accuracy Standards (Paper Maps)
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 6
13. “Source scale” is one determinant of positional ...
14. About Scale
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 7
15. Large and Small Scale Maps
16. Scale 1:100,000 (1 inch approx 1.58 miles)
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 8
17. Scale 1:24,000
18. Scale 1:10,000
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 9
19. Scale 1:2,000
20. Relation between positional error and scale
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 10
21. NMAS Standards
22. Digitizing paper maps adds error
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 11
23. Attribute accuracy
24. Logical Consistency
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 12
25. Completeness Is the data set “complete”?
26. Currency: Is the data set current? No!
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 13
27. Ensuring data quality
28. Ensuring data quality
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 14
29. Ensuring data quality
30. Documenting data quality
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 15
31. What positional accuracy do you need?
32. What attribute accuracy do you need?
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 16
33. GIS quality-related issues
34. Metadata is critical!
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 17
35. Web sites with more information
36. Learn more about metadata
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 18
37. Metadata examples
Tufts OpenCourseWare © 2008 Tufts University
Data Quality
OCW: Introduction to Geographic Information Systems (GIS) for Urban andEnvironmental Analysis (B. Parmenter)
Page - 19
