Experimental evaluation of positional accuracy estimates from a linear network using point- and line-based testing methods
Positional accuracy estimates of linear features based on their well-defined points can be significantly different than the accuracy estimates determined from their adjoining lines. A case study was conducted to determine both the cause of this difference as well as the relative effect of the number of points used in calculating the point-based accuracy estimate. Results showed that: (1) the difference between accuracy estimates was primarily due to dissimilar criteria for measuring closeness of primitive features; and (2) the current US requirement of using 20 well-defined points provided a reasonable estimation of accuracy for the case study. The differences in accuracy estimates described in this study should impact both the definition of geospatial accuracy standards, and the interpretation of geographical analyses with respect to error propagation.