Adjusting a Traverse

The Closure View handles all the traverse summary and adjustment functions of TPC. To open the Closure View, open the Traverse View for the traverse you are interested in, then choose the Closure View command.

Edit Closure Types

A traverse's closure type affects how adjustments are applied.

You can adjust a Closed Loop traverse in which TPC assumes you are closing back on the initial traverse point.

You can also adjust a Closed Point to Point traverse in which you specify the closing point of the traverse and it's correct position (the position to close on).

To change the closure type choose Edit | Closure Settings | Closure Type to display the Closure Type dialog. Select the closure type you want and choose OK.

Edit Closing Points

The Closure View computes its summaries and adjustments starting with the Initial point (From) and ending with the Closing point (To). Together these are referred to as the Closing Points.

By default, TPC sets the Initial point to the first control point in the traverse and the Closing point to the last control point in the traverse.

To work with just a section of a traverse, choose Edit | Closure Settings | Closing Points. This brings up the Closing Point dialog. Recall the points you want to adjust From and To and choose OK. The Closure View will display the summary information using the new closing points and any adjustments made will affect only these points. Use this command to balance a traverse that runs through several known points in sections.

If you return to the traverse and add or delete points, the closing points will be reset to their default values.

To display the closing points in the Closure View, choose View | Include Closure Data | Closing Points

Editing Closing Angle

The closing angle is generally the last angle turned to close out the traverse to a known direction (bearing or azimuth), allowing TPC to compute a angular error.

Choose Edit | Closure Settings | Closing Angle to display the Closing Angle dialog.

TPC computes the difference between the computed and correct bearing/azimuth to get the angular error. This is the angular error that will be displayed in the Closure View. When you balance angles, TPC prorates the angular error among all the angles, including the closing angle.

Note: Angles are not actually balanced until you choose the Balance Angles command.

To see what the adjusted closing angle is after you have balanced the traverse, return to the closing angle dialog box. TPC remembers the closing angle you entered. If you undo all adjustments after the traverse has been balanced, this dialog box will display your original closing angle.

Adjustments

A number of adjustments are available from the Closure View. The Least Squares Network adjustment is available from the TPC Desktop.

You can choose from any of the following adjustments.

Balancing Coordinates
Balancing Angles
Curvature and Refraction
Applying a Scale Factor
Applying Precision
Least Squares - Traverse Adjustment

If you have the Professional edition, you can also apply the following PLSS adjustments:

Grant Boundary
Irregular Boundary

Undoing Adjustments

If you have adjusted a traverse, you can always undo the adjustments you have made. TPC does this by retaining the raw data with the traverse and simply recomputing the traverse using the raw data. This cancels any adjustments that have been made to traverse points including the closing angle, if you entered one.

You can use this option to cancel all adjustments, including the sticky adjustments (Precision, Curvature and Refraction, Scale Factor) and start over again.

One side effect is that any rotated or translated points in the traverse will be unrotated or untranslated as they are recomputed.

Distance and Direction Types

The Closure View displays data based on the Distance and Direction types selected for that traverse. The types are listed immediately under the Closure View heading at the top.

Distance Units

The distance units displayed in the Closure View are determined by the traverse units.  You set these in the Advanced tab of the Traverse View Format dialog.

Related Topics

Traverse Closure
Closure View
Check the area and perimeter of the traverse
Check the raw closure
Balancing Coordinates
Balancing Angles
Curvature and Refraction
Applying a Scale Factor
Applying Precision