The Preferences page is where you define various settings for computations for the current project. Preferences are saved to disk with the current project.
To create a UTM or 3TM zone, select the User-Defined Transverse Mercator zone and enter the applicable parameters in the Transverse Mercator column.
If the Standardized Residual threshold value is set to zero, Columbus will calculate a threshold value based on the Tau statistic. The Tau statistic thresholdis a function of the number of observations, the degrees of freedom and the confidence level set up for the network.
If you enter a non-zero value (for example, 2.0 seconds) in the Azimuth edit box, during adjustment each of these three individual azimuth SDs will be replaced with an SD of 2.0 seconds. Set the Azimuth edit box back to zero to use the observation-specific SDs during adjustment (3.0, 10.0 and 8.5, respectively).
If you enter a scaler of 1.5 in the Azimuth edit box, during adjustment each of these three individual azimuth SDs will be replaced with a SD of 1.5, 3.0 and 4.6 seconds, respectively. Set the Azimuth edit box back to 1.0 to use the original observation SDs during adjustment (1.0, 2.0 and 3.0, respectively).
R = Radius of earth + Ellipsoidal Height at the AT station.
Note: To turn all settings off in this tab, set each field to Zero.
Always enter latitude and longitude in DD.MMSSsss format. When using GPS vectors in 2D or 3D Local NEE networks, be sure to provide the best possible approximate latitude and longitude, based on one of your 2D or 3D fixed stations.
All adjustment computations in Columbus are based on an ellipsoidal height-based model; therefore, approximating ellipsoidal height will produce more accurate results. For projects covering a small area, this improvement may be negligible: the adjusted heights will still be orthometric heights.
When weighting by number of setups or distance, the weight is calculated by the formula:wgt = 1.0 / num setups
1.0 / distance.
When weighting by standard deviation, the weight is computed identically to how it is done in 2D and 3D networks (for all observations):wgt = 1.0 / standard deviation squared
wgt = 1.0 / variance.
Set the Rotation check boxes to rotate GPS vectors, if applicable, during adjustment to better fit the existing control in the project.
This requires a minimum of three control stations fixed in height and two control stations fixed in 2D. Some possible ways to satisfy include:
Use to select all reports you want to generate during network adjustment. Some reports may not be applicable to the adjustment you are currently performing; for example, Error Ellipsoids will not be generated when performing a 1D or 2D adjustment.
Information about releases.