Reverse Affine Transformation


This sample shows you how to create a new Spatial Adjustment transformation method using a reverse affine transformation as an example. This method performs an affine transformation in the reverse or backward direction from the displacement links. It is often used in Spatial Adjustment applications where data is first transformed in a forward direction, edited, then transformed back to its original location using the same transformation parameters.

A similar sample, Reverse Adjustment, also demonstrates this by using two forward adjustments but produces a less accurate result.

How to use:
  1. Register the dll.
  2. Use the category manager to add ReverseAffine.dll to the 'ESRI Adjustment Transformation Methods" component category.
  3. In ArcMap, create some displacment links and save these to a file.
  4. Select some data and perform a normal affine transformation.
  5. Keeping the selected set, load the saved link file, set the adjustment method to reverse affine and adjust.

ArcMap: Spatial Adjustment

Requires: Edit Session

Minimum ArcGIS Version Required: 8.2

Difficulty: Intermediate

Visual Basic
File Description
RevAffineTransformationMethod.cls Reverse adjustment class.
RevAffine.vbp Visual Basic 6 project file.
ReverseAffine.dll The compiled dll.

Key CoClasses: AffineTransformation2D
Key Interfaces: ITransformationMethod, ITransformationMethodRMSError, IAffineTransformation2D, ITransform2D
Key Members: ITransform2D::Transform