View and Edit Mean Angle Residuals

A mean angle represents the combining and averaging of redundant observations to the same point. You can view residuals for each observation used to calculate a mean angle using the Mean Angle Residuals dialog. If a residual for an observation exceeds tolerances specified in the Computations > Mean Angles tab in Project Settings, the observation includes a red flag. The observation is deemed an "outlier" and you should consider disabling it, along with the other observations in the set, so it is not used to compute the mean angle.

Note: For mean angle residuals, all angles are normalized to the range of 0 to 360 degrees expressed in project units. All distances are displayed in project units.
Note: If you delete a mean angle from your project (that is, right-click the mean angle node in the Project Explorer and click Delete), all observations associated with the mean angle are also deleted.

To view and edit residuals for a mean angle:

To display the Mean Angle Residuals dialog, do either of the following:
- Right-click the mean angle node icon in Project Explorer and select Mean Angle Residuals from the context menu.
- Select the mean angle in Plan View, then right-click and select Mean Angle Residuals from the context menu.
If a mean angle includes an outlier observation (that is, the observation exceeds tolerances specified in the Computations > Mean Angles tab in the Project Settings dialog), the node name is displayed in red in the Project Explorer. In addition, the mean angle includes a red error flag in the Plan View.
In the Mean Angle Residuals dialog, review the read-only data displayed in the various boxes in the top half of the dialog.
In the table, review the observations used to compute the mean angle and their residual values.
If a residual for an observation exceeds tolerances specified in the Computations > Mean Angles tab in the Project Settings dialog, the observation includes a red flag.
If necessary, uncheck the box in the Enabled column for any observation that you do not want used in the computation of the mean angle.
Typically, you would uncheck (disable) any outlying observations, which include red flags. When you uncheck an observation, you are prompted to disable all observations in the set. To avoid errors, it is recommended that you disable all observations in the set so they are not used to calculate the mean angle(s).
Note: One set of observations may be used to calculate more than one mean angle. If you disable all of the observations in the set for one mean angle, you are disabling the entire set for any other mean angles it was used to calculate.
As you enable or disable observations, the means and residuals are re-calculated so you can immediately see the effects of the change. However, these changes are temporary and do not apply to the project until you click Apply or OK.
Optionally, click Report to view the Mean Angle Report.
Note: If you uncheck (disable) an observation, the Report button becomes disabled. You must click the Apply button to save your changes to re-activate the Report button.
When you are done, click Apply or OK.

Note: To better estimate standard errors, the software removes collimation errors from the point pairs prior to calculating residuals for mean angles.