Objectives Differentiate accuracy, precision, error, and uncertainty. Discuss the dimensions of geographic data quality. Discuss how to compute RMSE for positional accuracy. Describe why data standards are beneficial Key terms: metadata
Accuracy—how close to “true” Precision—how exactly measured and stored Error—deviation from “true” value Uncertainty—lack of confidence due to incomplete knowledge
Inherent = Source Operational = user or processing
Semantic Discrepancies
RMSE = sqrt(average(squared discrepancies)) x, y, and z (or e) p = sqrt(x²+ y²) (Positional) Use p and e for map overall
Metadata—Geographic Data Quality Lineage Positional accuracy Attribute accuracy Logical consistency Completeness
Spatial autocorrelation
Sampling
Standards vs Translators