|
This page contains miscellaneous Least Squares settings.
File
Lists the current Least Squares Data file. If you working with a Least Squares network, this file fill have the same name as the survey file. In the case of a traverse adjustment, the filename is a combination of both the survey and traverse names. The filename is listed here for your reference only. You can not change the name.
Save As
Choose this option to write a TPC Least Squares data file (LSA extension) to record the state of the survey points involved in the adjustment. The saved file becomes a backup record of what you have done. You might choose this option to save a network you are building at each stage of its development.
You may never use the files you and TPC does not currently allow you to open them. You can however, rename any one of these files to the survey filename and it will become the current analysis for the survey.
Redundant Observation
TPC treats this character as a redundant observation indicator when it is the first character in a point description and is followed by a valid point label. This allows any data collector to collect redundant information regardless of whether or not it can include a shot to an existing point.
Example: If a shot to point 100 includes the description “#17 1” I.P.”, the Least Squares analysis will interpret this as a redundant observation to point 17.
If you include additional information in the point description like the 1”I.P. in the example above, the additional information must be separated from the point label by a space, colon or comma.
Blunder Factor
Enter the factor above which you want TPC to report blunders. A blunder is considered to have occurred if the computed residual value of an observation is greater than the APRIORI value for that type of observation multiplied by this factor.
Apply computed Reference Standard Deviation even if Chi Squared passes
Off (default) - TPC does not apply the Reference Standard Deviation.
On - TPC applies the Reference Standard Deviation even if the ChiSquared test passes
When TPC reports error ellipses and standard deviations of coordinates and standard deviations of individual observations, it can factor them by the computed Reference Standard Deviation. This setting allows you to tell TPC whether or not to do this.
In classic statics, if the Chi Square test passes, it means that the computed reference variance is not statistically different from the aPriori value (estimate of the reference variance) of 1.0. More specifically in statistical language, it means that the test fails to reject the null hypothesis that the computed reference variance == 1.0.
In other words, we can use 1.0 to factor any errors that we report for the data. But we could also use the computed reference variance since it is not statistically different from 1.0.
Keep in mind that the computed Reference Standard Deviation (also reported) is just the square root of the computed Reference Variance. So if you choose to accept and use the Reference Variance of 1.0, the Reference Standard Deviation is also 1.0.
Error Ellipses
Draw
Include the error ellipses in Drawing View. You must have solved for a Least Squares solution for ellipses to be plotted.
Draw for unadjusted points
Off (default) - TPC only draws the error ellipses if [x] Draw is turned on and the current Least Squares solution has been used to update and adjust points.
On - TPC draws the error ellipses, if [x] Draw is turned on, even if the current Least Squares solution has not yet been used to update adjusted points.
This setting lets you view error ellipses prior to accepting the solution and updating your points. Use it to get a visual indication of how good your current solution is and where you might need to improve it.
This setting has no affect if [ ] Draw is not turned on.
Major-Axis: Max Length
When TPC draws error ellipses for a drawing, it must exaggerate the scale of the ellipses in order for you to see them.
This value determines the size of the ellipse with the longest major-axis (error). All other error ellipses will draw smaller than this one.
A Priori Values
Choose this option to display the Least Squares Standard Errors dialog. From this dialog you can change the default standard errors to use in the analysis. These values are incorporated into the analysis as the coordinate and observations records are being created. Of course you can always change them later by editing the Points or Observations.
Write Starnet File
Choose this option to write a Starnet V4.0 compatible data file. TPC uses the survey filename along with the .DAT extension used by Starnet. This file can be opened in Starnet and analyzed.
Related Topics
Least Squares
Editions
Premium, Professional
|
