Positional Errors and Accuracy

Positional Errors and Accuracy

According to the ASPRS Positional Accuracy Standards for Digital Geospatial Data, the terms positional error and absolute and relative accuracy are defined as follow:

• Positional error – The difference between data set coordinate values and coordinate values from an independent source of higher accuracy for identical points.
• Positional accuracy – The accuracy of the position of features, including horizontal and vertical positions, with respect to a horizontal and vertical datum.
• Relative accuracy – A measure of variation in point-to-point accuracy in a data set.
• Relative accuracy – Characterizes the internal geometric quality of an elevation data set without regard to surveyed ground control.