Accuracy

EPE (the “Accuracy” shown on your GPS) is an estimation, rather than a measurement.

There is a difference between Accuracy and precision

To many people, accuracy and precision mean the same thing: to someone involved in measurement, the two terms should have very different meanings.

Accuracy - the degree of conformity with a standard

Precision - the degree of refinement in the performance of an operation

Look in your GPS manual and it will say something like “Accuracy of <15 meters”. This is it's degree of conformity to a standard i.e. within 15 meters of bulls eye. The EPE that is on your GPS however should often be as low as 4 meters. This is the degree of refinement in the performance of an operation. i.e a the uniformity of the co-ord within the aforementioned range of accuracy.

Accuracy