Ladies and Gentlemen, Boys and Girls, geometry nerds of all varieties! A short and sweet one for you this week folks.
If you would like to follow along at home, the data I will be using (which is an excellent dataset for practicing network adjustment routines) and detailed information/instructions can be found on the page TBC Tutorials. Use the “download link…” for Adjusting the Network under the section Performing common workflows to download this data as well as an instructional PDF for the network adjustments tutorial. Might I also take this opportunity to promote the fabulous help documentation in TBC, it can be accessed any time by pressing the F1 key, I find myself referring to it often.
In the Adjust Network command, when working with data of varying qualities or precisions, it is often useful to be able to adjust the standard errors associated with your measurements. In TBC the default setting is to have the components broken down into horizontal and height standard errors.
A nifty trick to add to the toolbelt for any geometry aficionado is about to be exposed. If you know about this already, congratulations! You’ve spent some time digging through the project settings and have discovered one of the many gems of TBC.
Go to project settings, this can be accessed through the quick access toolbar at the top of the TBC window, or from the top of the Adjust Network command pane.
Under Units > Coordinate, for Expand horizontal standard errors: Select “Yes”.
(Please excuse my display order set to Northing, Easting, Elevation if you’re a type that follows the Easting, Northing, Elevation convention, I like to stand out.)
Click Ok to close the project settings menu.
Notice now that the individual North and East standard error components can be adjusted to really dial in your network adjustment and achieve the best results to match your local conditions.
It is important to note, the check boxes associated with each point must be checked for the entered values to be used in the adjustment.
“The larger the value you enter, the more freedom the adjustment will have to move the adjusted position away from the control coordinate and the larger the error ellipses will be for fixed and propagated points.” -TBC help documentation
And there you have it folks! Hopefully you’ve been inspired today to open up an old project and see if you can squeeze a bit more improvement from those residuals. I know I have!