Basis of bearing

This topic applies to ArcEditor and ArcInfo only.

In some cases, when splitting an existing parcel, the new subdivision plan or record of survey has a basis of bearing. A basis of bearing is stated on a plan or record of survey when the origin of north on the document is different from north in your coordinate system. For example, the basis of bearing could be the bearing of a line between two control points or follow a particular boundary line on the plan or record of survey.

Basis of bearing
Basis of bearing description

When subdividing a parcel in the parcel fabric, you can use the Basis Of Bearing tool to orient or rotate the original parcel to the basis of bearing used on the new subdivision plan.

Basis of bearing
Basis Of Bearing tool

The Basis Of Bearing tool starts with a reference bearing to which the basis of bearing rotation will be applied. The reference bearing is the bearing of the parcel line on which you right-clicked to activate the tool. The basis of bearing that is entered is used to calculate the rotation or bearing offset that will be applied to the parcel.

Basis of bearing rotation
Basis of bearing rotation applied to parcel

The reference line/bearing can be changed at any time by clicking the Change button, which loads a dialog box asking you to specify a new reference line. A new reference line is specified by clicking the from- and to-points of the line.


The Basis Of Bearing tool only works with the Construct from parent command. In other words, you will only use basis of bearing when subdividing parcels with construction line work.


The basis of bearing rotation is not a ground to grid correction. The scales of the original parent parcel and new parcels are represented on the ground in the parcel fabric. The least-squares adjustment will correct parcels to projected grid coordinates based on elevations of the control points used in the adjustment.

The basis of bearing rotation is a temporary rotation that is applied to the original parent parcel. The rotation is not stored on the parent parcel. However, the newly subdivided parcels will have the same orientation or rotation that was defined as the basis of bearing for the parent parcel.

    To apply a basis of bearing, follow these steps:
  1. In an edit session in ArcMap, click the Select Parcel Features tool Select Parcel Features on the Parcel Editor toolbar, right-click the parcel you want to subdivide, then click Construct from parent.
  2. If you are working in manual mode with fabric jobs, right-click the parcel you are subdividing in an open fabric job.
    Before applying the basis of bearing rotation, make sure the parcel is being displayed in parcel measurement view.
  3. Click the Parcel Editor menu and click Parcel Measurement View.
  4. NoteNote:

    In parcel measurement view, parcels are displayed using coordinates derived from their COGO dimensions instead of their fixed, joined locations in the parcel fabric layer. To view the basis of bearing rotation on the parcel, the parcel must be displayed in parcel measurement view. Parcels are automatically displayed in parcel measurement view when opened in a local coordinate frame.

  5. On the open parcel, right-click the parcel line that will be used as the reference bearing for the basis of bearing rotation and click Basis of Bearing.
  6. On the Basis of bearing dialog box, type the basis of bearing in the Enter the new bearing text box.
  7. Click Calculate to display the rotation or bearing offset in the Bearing offset text box.
  8. Click Apply to apply the bearing offset or rotation to the open parcel.
  9. The map is refreshed to display the rotated parcel. You can now add construction lines to split the rotated parcel.

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