Interpretation of internal reliability¶
All distances, directions and any zenith distances are listed in the analysis list.
Reliability measures for observations¶
Each observation has its reliability measures:
- Largest remaining gross error
The outer edge of the confidence interval for the gross error at a given significance level is called the largest remaining gross error. Given with the observation's unit. That is, meters or gon.
- Redundancy
Varies between 0 and 1. Observations with small redundancy (close to zero) show little of any gross error in the adjustment corrections. They are therefore difficult to detect in gross error detection.
- Maximum relative gross error
Largest remaining gross error in multiples of the observation's standard deviation. If the value is, for example, 2, we can at a given significance level assert that the observation does not contain gross errors larger than its standard deviation × 2.
The summary list also shows some key information for internal reliability.
Non-testable observations¶
In several cases, the observations may be without control. Examples of this are simple polar measurements, but more complex cases can be imagined, such as the network shown below:
The direction from P2 to TP1 is not testable. It has no control. On the screen it is displayed with the most extreme color, and on the result output the redundancy gets the value 0.00, while maximum relative gross error gets the value 99.999. During internal reliability calculation, a message is given that at least one observation is not testable.
Graphical interpretation¶
It is the redundancies for the observations that are displayed on the screen. The other internal reliability measures cannot be documented on the screen.
As we can see in the figure below, the redundancy is shown with a thick line marking, and this line's placement indicates which observation the redundancy belongs to:
The distance between two points is divided in two. The redundancy marking refers to an observation from the nearest point. Each half is again divided into three. If the redundancy marking is closest to the point, it refers to a distance, then to a direction and finally to a vertical angle.