GeographicBufferer

Creates a buffer zone of specified size around or inside input geometry. Works similarly to the Bufferer, but is designed for use with features in Geographic coordinates. Reprojects input features into the Dynamic Equal Distance projection, buffers them, then reprojects back into the original Geographic coordinates.

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Typical Uses

Creating fixed size zones around features, such as rights-of-way or setbacks
Determining spatial relationships based on proximity
Creating variable size zones around features to represent attribute values
Creating a buffer in different units than the input data

How does it work?

The GeographicBufferer accepts 2D point, curve (line), and area geometries. It reprojects the input features, including those with geographic (lat/long) coordinates, to Dynamic Equal Distance projection, and then creates buffers according to the parameter settings for units, size, and style.

The buffers are then reprojected to match the original coordinate system of the input features, and are output.

Point and lines may be expanded, creating surrounding polygons with points offset by the specified Buffer Amount in ground units. Areas may be expanded or shrunk, using positive or negative Buffer Amounts.

The attributes of the original features are retained, and the buffer is output, discarding the original geometry.

A selection of end cap and corner styles is available.

Usage Notes

This transformer creates buffers that are of equal width on either side of a linear input feature. To create offsets to either the left or right-hand side of a feature, use the OffsetCurveGenerator along with a Reprojector.
To buffer features not in Geographic (lat/long) coordinates, consider the Bufferer.
Areas will be buffered on one side only - externally for a positive Buffer Amount, and internally for a negative Buffer Amount.
Features must have a coordinate system defined, or they will be output via the Rejected port. The CoordinateSystemSetter may be of use to specify coordinate system if it is missing.
The GeographicBufferer will buffer features in any valid coordinate system (geographic or other), and so may be used to create flexible workspaces that can buffer regardless of input coordinate systems and units.

Configuration

Input Ports

Output Ports

Parameters

User Parameters

Buffer Distance Unit	This parameter specifies the measurement units used by the Buffer Distance parameter. Choices include: Feet Kilometers Meters Miles
Buffer Distance	If a positive (negative) buffer amount is specified, the input feature is expanded (shrunk). A buffer amount of 0 will leave the input geometry unmodified.
End Cap Style	When buffering a line, you can specify the end-cap style. As these diagrams illustrate, these caps can be Round (default) or Square, but you can also set this parameter to None. Round Square None
Corner Style	When buffering a line or area, you can specify the corner style. As the diagrams below illustrate, the corner styles can be Round (default), Bevel (chopped), or Miter (pointed). If Miter is used, a limit must be specified using the Miter Limit parameter. If a corner is too pointed for the miter limit, the corner will instead be bevelled. Round Bevel Miter
Interpolation Angle	This parameter controls the smoothness of the stroked arcs in the output buffer boundaries. It specifies what angles should be used to construct a circular arc. As this parameter decreases in value, the smoothness of the arc connectors increases. This parameter is used for the Round End Cap Style and the Round Corner Style. The value must be between 0 and 90 degrees.
Miter Limit	Miter Limit This parameter controls how pointed a buffered corner can be before it is beveled. It is the highest value that the ratio of corner distance to offset is allowed to have before truncation occurs. A higher number allows for more extreme corner angles. Black line: Original line Red line: Offset curve A: Corner distance B: Offset Miter Ratio = Corner distance / Offset

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 - whether entered directly in a parameter or constructed using one of the editors.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies
FME Licensing Level	FME Professional Edition and above
Aliases
History
Categories	Spatial Analysis

FME Knowledge Center

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Examples may contain information licensed under the Open Government Licence – Vancouver

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.
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.
Working with User Parameters	Create your own editable parameters.