Technical information

234 | Chapter 19 Adjusting Data and Working with Figures
Editing and Adjusting Survey Data
You can use several methods to edit and adjust your survey data for closure.
The traverse adjustment tools use the data you entered in the observation
database. These adjustments can update both your project points and the
line work entered with your survey.
Figures represent the line work from the survey. You can use these lines to
check bearings and distances, and to provide descriptions for boundary areas
or linear features. You can also use figures to make breaklines for the terrain
modeling functions in your project.
TIP The Survey Toolspace interface enables you to view, manage, and edit the
traverse network and figures as well as edit individual observations. You can pre-
view figures and also flag specific figures to use as surface modeling breaklines.
For more information, see Survey Toolspace and Panorama in the online Help.
Adjusting a Traverse
When you adjust a traverse, all the directions and distances along the
traverse loop are calculated to establish traverse point coordinates. For a
closed traverse loop, the endpoint should match the start point. The
traverse loop may not close exactly because of instrument inaccuracy and
human error, but if it closes within a user-specified tolerance, then you can
adjust the traverse.
Survey provides four methods to adjust traverse information:
■ Compass Rule: A corrections method where the closing errors are
assumed to be as much due to errors in observed angles as errors in mea-
sured distances. The closing errors in latitude and departure are distrib-
uted according to the ratio of the length of the line to the total length of
the traverse.
■ Crandall Rule: A method of balancing a traverse where all the angular
error is distributed throughout the traverse and all adjustments to the
traverse are due to modifying the traverse distances. The modification
distance made to each leg is such that the sum of the squares is a mini-
mum. Corrections corresponding to the closing errors assume that the
closing errors are random and normally distributed, and that all the angu-
lar error has been adjusted prior to the adjustment routine.