Running a fabric least-squares adjustment

This topic applies to ArcEditor and ArcInfo only.

A fabric least-squares adjustment should be run repeatedly until the maximum and average coordinate shifts become 0.0 or do not change.

Maximum and average coordinate shift of the least-squares adjustment

Each time an adjustment is rerun, an adjustment iteration has been performed. You are iterating an adjustment if you click Run on the Adjust Coordinates dialog box or Accept on the Least Squares Adjustment Summary dialog box, then click Run again on the Adjust Coordinates dialog box to run another adjustment iteration. Once OK is clicked on the Adjust Coordinates dialog box, the adjustment is completed with no more iterations. Once the maximum and average coordinate shifts become 0.0 or do not change, the adjustment has converged to an optimal solution.

Tip:

Adjustment postprocessing or plan structure constraints should be enforced only after adjustment convergence is reached. Line points tolerance and Straight line tolerance under Plan Structure Constraints on the Adjust Coordinates dialog box should remain unchecked until the adjustment has converged. Once the adjustment has converged, run the adjustment one more time with the Straight line tolerance and/or the Line points tolerance options checked.

Steps:

To run a fabric least-squares adjustment, follow these steps:
1. In an edit session in ArcMap, click the Select Parcel Features tool on the Parcel Editor toolbar and drag a box to select the parcels you want to adjust.
If you are working in manual mode using fabric jobs, select the parcels you want to adjust and click Parcel Editor > Modify to open the selected parcels in a fabric job. All parcels in the open fabric job are adjusted.
Tip:

You do not need to select control points because active control points are linked to fabric points. Control points are automatically detected on the points of selected parcels.



Note:

A minimum of two control points are required to run a fabric least-squares adjustment.

2. Click the Parcel Editor arrow and click Adjust.
3. On the Adjust Coordinates dialog box, type the tolerances you want to use in the Bearings, Distances, Line Points, and Close Points text boxes or accept the defaults.
4. Choose which constraint you want to enforce under Plan Structure Constraints and type the tolerance you want to use. You can choose to enforce both constraints.
5. Click the Treat dependent lines as standard boundary lines check box if you want dependent lines to participate in and influence the outcome of the adjustment. If you leave this option unchecked, dependent lines will not influence the outcome of the adjustment but will adjust along with the parcel upon which the parcel is dependent.
6. Click the Report type arrow to choose the adjustment report type. In an extended report, every parcel line and its adjustment are listed.
7. Click the browse button to browse to a location to save a log file of the adjustment, or accept the default location.
8. Click Run to run the adjustment and display the adjustment report on the Least Squares Adjustment Summary dialog box.
9. On the Least Squares Adjustment Summary dialog box, click the Results File button to save the adjustment report as a text file.
10. If the adjustment is successful and the adjustment statistics are acceptable, click the Accept button on the Least Squares Adjustment Summary dialog box to accept the adjustment iteration and close the dialog box. To reject the adjustment, click the Cancel button.
11. If you do not want to rerun another iteration of the adjustment, click OK on the Adjust Coordinates dialog box to complete the adjustment.
Note:

Any parcel lines that need to be adjusted by greater than three times the distance or bearing tolerance will cause the adjustment to fail.

Tip:

On the Least Squares Adjustment Summary dialog box, click any of the line errors listed under Parcel Line Report and click the Select Parcels button to select the parcel with the erroneous line in the map. You can also click the Map Location button to pan or zoom to the parcel.

Tip:

When the adjustment is completed, parcels that are adjacent to the adjusted parcels receive the same adjustments. This allows seamless reintegration of the adjusted parcels into the parcel fabric.

Tip:

The difference between the original recorded line dimensions and the dimensions of the adjusted line geometry is stored in the ComputedMinusObserved field in the parcel lines attribute table.