Points After Calculation¶
Abstract
Here you will find an overview of columns in the result display and an explanation of the error ellipse used in the calculation.
Column Explanations¶
| Column | Description |
|---|---|
| PointID | Point designation depending on the selected identity type |
| N-coord. | Northern coordinate value |
| E-coord. | Eastern coordinate value |
| Height | Orthometric height (distance along the plumb line from the geoid) |
| Std. N | Standard deviation of the point's north coordinate |
| Std. E | Standard deviation of the point's east coordinate |
| Std. H | Standard deviation of the point's height coordinate |
| a | Major semi-axis of the error ellipse |
| b | Minor semi-axis of the error ellipse |
| fi | Direction angle of the major semi-axis |
Error Ellipse¶
Info
The probability that the true coordinate value lies within the error ellipse is 39.3% when the standard deviation* is well determined with many (theoretically infinite) redundant measurements.
Definition¶
The ellipse is defined by three parameters:
- Major semi-axis a
- Minor semi-axis b
- Direction angle fi for major semi-axis
Geometric Interpretation¶
The standard deviation in any arbitrary direction can be shown geometrically as in the figure below. The standard deviation equals the distance from the center (P) to the ellipse's tangent perpendicular to this direction.
Geometric representation of standard deviation and error ellipse
Note
*) Calculated/estimated standard deviation of unit weight.