Error, Accuracy, and Precision

Table of Contents

1. The Importance of Error, Accuracy, and Precision

2. Some Basic Definitions

3. Types of Error

• 3.1. Positional Accuracy and Precision
• 3.2. Attribute Accuracy and Precision
• 3.3. Conceptual Accuracy and Precision
• 3.4. Logical Accuracy and Precision

4. Sources of Inaccuracy and Imprecision

• 4.1. Obvious Sources of Error

 

• 4.1.1. Age of Data
• 4.1.2. Areal Cover
• 4.1.3. Map Scale
• 4.1.4. Density of Observations
• 4.1.5. Relevance
• 4.1.6. Format
• 4.1.7. Accessibility
• 4.1.8. Cost

 

• 4.2. Errors Resulting From Natural Variation or From Original Measurements

 

• 4.2.1. Positional Accuracy
• 4.2.2. Accuracy of Content
• 4.2.3. Sources of Variation in Data

 

• 4.3. Errors Arising Through Processing

 

• 4.3.1. Numerical Errors
• 4.3.2. Errors in Topological Analysis
• 4.3.3. Classification and Generalization Problems
• 4.3.4. Digitizing and Geocoding Errors

5. The Problems of Propagation and Cascading

• 5.1. Propagation
• 5.2. Cascading

6. Beware of False Precision and False Accuracy

7. The Dangers of Undocumented Data

• 7.1. Ask for a Data Quality Report
• 7.2. Prepare a Data Quality Report
• 7.3. Ask Questions abour Undocumented Data

8. Principles of Managing Error

9. Required Readings

10. References and Further Readings

11. Examination and Study Questions