AffineWarper

From Fmepedia

AffineWarper is a Workbench Transformer.

Performs warping operations on the spatial coordinates of features. It is used to adjust a set of observed features so they more closely match some set of reference features. This transformer computes an affine (scale, rotation, and offset) transformation based on CONTROL vector features and applies this transformation to the OBSERVED features to generate output, and produces good corrections when the entire set of OBSERVED data requires a single transformation.

The RubberSheeter transformer provides similar functionality but applies a different transformation to each OBSERVED vertex, depending on its distance to nearby CONTROL vectors. This makes the RubberSheeter more appropriate for cases when the distortions in the data are not constant.

Two sets of features must be routed into this transformer. Features entering via the CONTROL port represent the control features used to compute the corrections. Features entering via the OBSERVED port are the features which will be corrected.

The modified OBSERVED features are output via the CORRECTED port.

Each CONTROL feature represents a control vector whose start point is at some location in the original OBSERVED data space, and whose end point is at the corresponding location in the desired output data space. The control vector represents the correction required to go from the observed vertex to the desired vertex. (Control vectors with only one point are interpreted as a requirement that this location not change from the observed dataset to the reference dataset. This is often referred to as a tie point.)