Performs an affine transformation on the coordinates of the feature.
An affine transformation preserves lines and parallelism in geometry. That is, any lines that were parallel before the transformation are parallel after the transformation. In addition, if a number of points falling on a straight line are transformed, the resulting coordinates will fall on a straight line in the new coordinate system.
Affine transformations include translations, rotations, scalings, and reflections.
Input Ports
Input
This transformer accepts all features. Arcs and ellipses are preserved.
Output Ports
Affined
The transformed features.
<Rejected> (Dynamic)
The dynamic <Rejected> port appears when a parameter is set to a non-literal value that might make processing impossible.
For example, if a numeric parameter such as Line Width, Count Start, or Decimal Places is set to an expression, attribute value, or user parameter, it is possible to pass in a non-numeric value that cannot be used. Decimal Places = Cat cannot be processed, so the feature will be output via this port.
Rejected features will have an fme_rejection_code attribute explaining the reason for rejection.
Rejected Feature Handling: can be set to either terminate the translation or continue running when it encounters a rejected feature. This setting is available both as a default FME option and as a workspace parameter.
Parameters
Coefficients
Coefficient A to F
To use the Affiner, you need to provide the 6 parameters that drive the following affine transform equation:
x' = Ax + By + C
y' = Dx + Ey + F
Where (x,y) is the input point and (x',y') is the transformed output point.
Examples
Translating Features East and North
To move features 500 units east and 1000 units north, use the following formula:
x' = 1x + 0y + Easting
y' = 0x + 1y + Northing
x' = 1x + 0y + 500
y' = 0x + 1y + 1000
You would then enter the corresponding values for A to F in the Affiner parameters (for example, A=1, B=0, C=500, D=0, E=1, F=1000)
Scaling a Feature Set
To scale features by factor R, use the scale factor to the X and Y terms as follows:
x' = Rx + 0y + 0
y' = 0x + Ry + 0
To increase the scale by 10 times:
x' = 10x + 0y + 0
y' = 0x + 10y + 0
Rotating Features
To rotate features, apply the appropriate cos and sin functions associated with the rotation angle to the X,Y coefficients:
x' = cos(w)x + -sin(w)y + 0
y' = sin(w)x + cos(w)y + 0
where w = angle of rotation.
So, for a rotation of 30 degrees, cos(30) = 0.866025, sin(30) = 0.5, you would use:
x' = 0.866025*x + -0.5*y + 0
y' = 0.5*x + 0.866025*y + 0
to rotate a set of features by 30 degrees.
Combining Transformations
You can combine a set of transformations into one formula, or perform them in series to make it easier to debug or edit. For example, it may be easier to do your rotation and then scaling in two different Affiner transformers rather than trying to combine them into one transformation. Naturally, one advantage to doing it all in one transformation would be speed.
Note: Right-click on the transformer in the workspace and click Show Summary Annotation. This makes it easy to preview the transformation formula that will be used.
Related Transformers
- Please also see the AffineWarper, which performs warping operations on the spatial coordinates of features. The AffineWarper is used to adjust a set of observed features so they more closely match some set of reference features.
- The Scaler and Offsetter are both simplified versions of the Affiner. For example:
x' = Ax + By + C
and
y' = Dx + Ey + F
where A = 1000 and E = 1000
In this case, x' = 1000x and y' = 1000y is the same as Scaler.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click 
beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
Defining Values
There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.
How to Set Parameter Values
Using the Text Editor
The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.
Using the Arithmetic Editor
The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.
Conditional Values
Set values depending on one or more test conditions that either pass or fail.
Parameter Condition Definition Dialog
Content
Expressions and strings can include a number of functions, characters, parameters, and more.
When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.
Content Types
| These functions manipulate and format strings. | |
|
Special Characters |
A set of control characters is available in the Text Editor. |
| Math functions are available in both editors. | |
| Date/Time Functions | Date and time functions are available in the Text Editor. |
| These operators are available in the Arithmetic Editor. | |
| These return primarily feature-specific values. | |
| FME and workspace-specific parameters may be used. | |
| Creating and Modifying User Parameters | Create your own editable parameters. |
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Table Tools
|
Row Reordering
|
Enabled once you have clicked on a row item. Choices include:
|
|
Cut, Copy, and Paste
|
Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers. |
|
Filter
|
Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output. |
|
Import
|
Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers. |
|
Reset/Refresh
|
Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers. |
Note: Not all tools are available in all transformers.
FME Community
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Search for samples and information about this transformer on the FME Community.
Keywords: pointcloud