From this dialog, TPC can balance the portion of the current traverse defined by the closing points using the adjustment rule selected.

Error can be adjusted by selecting the Compass, Transit or Crandall method. The User may also specify whether or not elevations are to be balanced.

Note: We strongly encourage you to become familiar with both the strengths and weaknesses of these adjustment methods before putting any of them to use.

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## Summary of Methods of Balancing a Survey

The discussion relating to methods of balancing a survey may be summarized by the following statements:

• In many cases, a careful, arbitrary distribution of errors on the basis of a knowledge of the field conditions is the best that can be made.
• If systematic errors are believed to be present in the linear measurements, they can be eliminated only by applying the proper computed corrections to the field measurements before any rules for balancing the survey can be applied, since systematic errors are not subject to distribution by any general rule.
• If the error of closure is subject to accidental errors affecting angular and linear measurements equally, the Compass Rule is valid.
• In most cases, the Transit Rule cannot properly be used.
• If accidental errors in linear measurements are assumed to be much larger than those in angles, the Crandall Method is Valid.

Davis & Foote, Surveying, Fourth Edition.

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You cannot adjust coordinates if raw data does not exist. For more information on raw data refer to the Update Raw Data command in the Traverse View.

## Compass

Error distribution will be allocated based on the Compass method of error distribution.

The Compass Rule states that the correction to be applied to the lat/dep of any course is to the total correction in lat/dep as the length of the course is to the length of the traverse. It assumes that the errors in traversing are accidental and vary with the square root of the lengths of the sides. It also assumes that the effects of errors in angular measurements are equal to the effects of errors in distance measurements.

## Transit

Error distribution will be allocated based on the Transit method of error distribution.

The Transit Rule states that the correction to be applied to the lat/dep of any course is to the total correction in lat/dep as the lat/dep of that course is to the arithmetical sum of all the lat/dep of the traverse. It assumes that errors in traversing are accidental and that the effects of errors in distance measurement are greater than the effects of errors in angular measurements.

## Crandall

Error distribution will be allocated based on the Crandall method of error distribution.

The Crandall Rule applies a least squares adjustment to the length of each course. It assumes that the effects of errors in angular measurements are negligible or have already been adjusted out of the traverse. It further assumes that any adjustment should be applied only to the lengths of the courses.

## PLSS Lost Corner Restoration

TPC includes two options, Grant Boundary (PLSS) and Irregular Boundary (PLSS), that are port of the Cadastral tools of TPC Desktop. These are currently available only in the Professional Edition.

## Z

Balances elevations using the length of each leg to proportion the amount of adjustment.

It assumes that the correction to be applied to the elevation of any point is to the total correction in elevation as the distance along the traverse to the point is to the length of the traverse.

## OK

Adjusts the coordinates and returns you to the Closure View.

## Cancel

Returns you to the Closure View without making any adjustments.