Interpretation of Datasnooping¶
Interpretation of blunder detection is performed in the analysis list. In this window, you can choose to sort by columns.
Analysis List¶
The analysis list contains the following columns:
| Column | Description |
|---|---|
| Measured value | The observed measured value (units: gon and meter) |
| Assumed standard deviation | |
| Computed standard deviation | |
| Adjustment correction | Correction of the measurement so that it matches the adjustment result, \(v_i=\hat l_l-l_i\) |
| Redundancy (k-value) | Varies between 0 and 1. Observations with low redundancy (close to zero) show little of any blunder in the adjustment corrections, making them difficult to detect. |
| MDE (Baarda) | MDE (minimum detectable error) indicates the smallest blunder that can be detected using datasnooping. |
| External reliability (Baarda) | Baarda value |
| Sigma level | Test ratio |
Graphical Display¶
On the map, blunders in observations are marked. A sigma value greater than 3 is shown in dark red, and a sigma value from 2 to 3 is shown in light red:
Descriptions are shown below the images.
The observation line is divided in two, and three symbols are used as shown in the figure below:
The distance between two points is divided in half. The blunder marking refers to an observation from the nearest point. Each half is further divided into three. If the blunder marking is closest to the point, it refers to a distance, then to a direction, and finally to a vertical angle.