16. Human Error v Measurement Uncertainty

When surveyors refer to error models they are usually referring to the inaccuracies of instruments or measurement systems. Clearly these cannot compensate for bad practice and human error such as using grid North instead of True or GPS on the wrong datum. The instrument inaccuracies are often referred to as modellable errors whereas the practical mistakes are referred to as unmodellable errors. Great care has to be taken when using industry standard error models to ensure that best practice has been adopted before assuming that the calculated uncertainties are representative. The following section points out a few common mistakes.