AttributeCreator

Adds one or more attributes to the feature and optionally assigns a value derived from constants, attribute values, and expressions. Values can reference adjacent features.

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Typical Uses

Add a new attribute to a feature and assign it a value
Add a new empty attribute to a feature for use elsewhere in the workspace

How does it work?

Blank rows are provided where you can enter new attribute names and (optionally) set values for them. One or more new attributes may be added, and all features that pass through the transformer are modified according to these selections.

New attributes are added at the top. Duplicate names are not identified, and are not added more than once.

Examples

Advanced Example: Using Multiple Feature Attribute Support

Adjacent Feature Attributes are accessed under Advanced: Attribute Value Handling. When turned on, you can specify a number of features preceding and following the current feature to reference in calculating new values.

Suppose we are given the dataset below:

ID	Latitude	Longitude
0	49.1640	-123.061
1	49.1643	-123.063
2	49.1642	-123.062
3	49.1642	-123.064

If the Number of Prior Features and Number of Subsequent Features parameters are both set to 2, then when the first feature is read, the AttributeCreator has access to the following features:

Feature Reference	ID	Latitude	Longitude
feature[-2]	<missing>	<missing>	<missing>
feature[-1]	<missing>	<missing>	<missing>
current feature	0	49.1640	-123.061
feature[+1]	1	49.1643	-123.063
feature[+2]	2	49.1642	-123.062

Note that some attributes are missing because no features exist prior to the first feature.

After the second feature is read, the window of prior and subsequent features available to the AttributeCreator shifts to produce the following:

Feature Reference	ID	Latitude	Longitude
feature[-2]	<missing>	<missing>	<missing>
feature[-1]	0	49.1640	-123.061
current feature	1	49.1643	-123.063
feature[+1]	2	49.1642	-123.062
feature[+2]	3	49.1642	-123.064

This statement would calculate the average latitude of the two preceding features:

Calculations referencing adjacent features can be created in the Arithmetic Editor and the Text Editor. These editors will list the attributes of the currently processed feature first, then the prior features, then the subsequent features.

Usage Notes

Consider using the AttributeManager instead

Configuration

Input Ports

Output Ports

Parameters

Advanced: Attribute Value Handling

Substitute Missing, Null, and Empty by

Specifies the desired behavior when the referenced attribute does not exist, has a null value, or has an empty string value.

Such attributes can be thought of as unresolved attributes. For example, since there are no features prior to the first input feature, the AttributeManager will fail to resolve the value of feature[-1].AttrName for the first input feature.

If this parameter is set to No Substitution, the AttributeManager will resolve all unresolved attributes with an empty string if they are used in a larger expression. If the unresolved attribute is assigned directly and is not part of a larger expression, then the Output Attribute will be unresolved in the same way. For example, if B is missing, and A is set to @Value(B), then A will be missing as well. But if A is set to "B = @Value(B)", A will have the value of "B = ".

As another example, if the value of feature[+2] is the empty string and Default Value is specified, then the empty string will be treated as an unresolved attribute, and will be resolved as the value specified under Default Value.

If this parameter is set to Closest Adjacent Feature, then the unresolved attributes will be resolved as the corresponding attribute of the closest feature, if such a feature exists. When looking for closest features, features with unresolved attributes are skipped. If a prior or subsequent feature has unresolved attributes, it is possible that the current feature is used to resolve the missing attributes.

For example, if the value of feature[-2].AttrName is unresolved, then to resolve the value of feature[-2].AttrName the AttributeManager will look at the closest features to feature[-2], alternating between features prior to and subsequent to feature[-2]. It will first look at feature[-3].AttrName, followed by feature[-1].AttrName if needed, and then feature[-4].AttrName if needed, until all prior and subsequent features specified have been exhausted.

If the attribute remains unresolved within the specified prior and subsequent features, then it will be resolved as the value specified in the Default Value parameter.

Default Value

This parameter specifies the value used to resolve unresolved attributes in these cases:

Substitute Missing, Null and Empty by: is set to Default Value
Substitute Missing, Null and Empty by: is set to Closest Adjacent Feature and a value is not found in within the number of prior and subsequent features specified.

Enable Adjacent Feature Attributes

When enabled, you may set an attribute value (in the Attribute Actions table) based on the attributes of features prior or subsequent to the current feature by referencing them as follows:

Attributes of prior features are referenced as feature[-1].AttrName, feature[-2].AttrName, and so forth.
Attributes of subsequent features are referenced as feature[+1].AttrName, feature[+2].AttrName, and so forth.
Attributes of the currently processed feature are accessed directly without a prefix, such as AttrName.

When retrieving the value of a prior feature, any changes made by the AttributeManager to that feature will take effect.

Number of Prior Features

This parameter specifies the maximum number of prior features that can be referenced by the AttributeManager.

If Multiple Feature Attribute Support is enabled, this must be a value from 0 to 100.

As additional features must be read for each feature processed, defining only the maximum number of features needed to be retrieved will improve performance.

Number of Subsequent Features

This parameter specifies the maximum number of subsequent features that can be referenced by the AttributeManager.

If Multiple Feature Attribute Support is enabled, this must be a value from 0 to 100.

As additional features must be read for each feature processed, defining only the maximum number of features needed to be retrieved will improve performance.

Attributes To Create

When an AttributeCreator is opened for the first time, this area will contain a blank row where a new attribute can be created. Additional rows are added as entries are made.

New Attribute

Enter the name of the new attribute.

Names may also be assigned using expressions or the context menu to retrieve existing attribute values, User Parameters, or assign conditional values.

Attribute Value

New attributes can be left without a value for use elsewhere, or you can set new values here by clicking in the appropriate row and:

Entering a new constant value
Entering an expression
Selecting another attribute to copy values from
Using any of the available tools in the drop-down context menu to create expressions, formulas, conditional values, and more. The ellipses button will open the Text Editor, and the arrow button provides further options on the context menu.

See Defining Values below for detailed information on using these options.

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.

Text Editor

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.

Arithmetic Editor

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

String Functions	These functions manipulate and format strings.
Special Characters	A set of control characters is available in the Text Editor.
Math Functions	Math functions are available in both editors.
Date/Time Functions	Date and time functions are available in the Text Editor.
Math Operators	These operators are available in the Arithmetic Editor.
FME Feature Functions	These return primarily feature-specific values.
FME Parameters	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:

Add a row
Remove a row
Move current row up one
Move current row down one
Move current row to top
Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

Cut a row - delete and copy to clipboard
Copy a row to the clipboard
Paste a row from the clipboard

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.

Reference

Processing Behavior	Feature-Based Exception: Enable Adjacent Feature Attributes
Feature Holding	No
Dependencies	None
FME Licensing Level	FME Base Edition and above
Aliases
History

FME Community

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Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.