FME Transformers: 2025.0

Categories
Data Quality

Data Quality

Geometries

Geometries

Related Transformers
Generalizer
Categories
Data Quality

Data Quality

Geometries

Geometries

Related Transformers
Generalizer

SpikeRemover

Removes spikes from line, path, and area geometry.

Jump to Configuration

Typical Uses

  • Data QA and cleaning
  • Generalization

How does it work?

The SpikeRemover receives features with line, path, or area geometry and removes vertices that create angles less than or equal to a specified maximum between zero (0) and 180 degrees.

Spikes can be removed either in a single pass through the feature or iteratively, where new spikes created by spike removal are also removed until none remain.

Polygons with spikes created by their first or last points will have those spikes removed. Closed lines, however, will not. Consecutive duplicate points are also removed, whether or not they occur in a spike.

Donut polygons and aggregate geometries are supported.

Altered and unaltered geometries are output, as well as any removed vertices as points. If Remove Spikes Iteratively is No, the Removed points will receive attributes with spike angle and length.

Z values are optionally supported.

A Maximum Spike Length may be specified, and the shorter of the two sides is considered to determine overall spike length. In most cases this parameter should remain blank.

Examples

In this example, we have a polygon and want to remove a spike from it. Note there are two candidates that could be spikes.

The feature is routed into a SpikeRemover. In the parameters dialog, Maximum Spike Angle is set to 10 degrees.

The smaller of the two spikes falls under the maximum, and so its central vertex is removed. The removed vertex is output via the Removed port and receives new attributes indicating angle and length.

Note a second vertex with an angle and length of zero (0). This was a consecutive duplicate vertex, which has also been removed but does not affect the shape of the output geometry.

Usage Notes

  • The SpikeRemover is not effective when the geometry has many deviations other than spikes. Consider using a Generalizer with the Douglas-Peucker algorithm.

Configuration

Input Ports

Features with line, path, or area geometry.

Output Ports

Any features modified as specified in parameters, either from spikes or consecutive duplicate vertices.

Features without spikes or consecutive duplicate points, unmodified.

Removed vertices are output here.

When Remove Spikes Iteratively is No, these attributes are added:

  • _spike_angle
  • _spike_length1
  • _spike_length2

Features with geometry other than valid line, path, or area geometry are output via this port, as are any features that receive non-numeric values for any numeric parameters.

Rejected features will have an fme_rejection_code attribute with one of the following values:

INVALID_GEOMETRY_TYPE

INVALID_PARAMETER_ANGLE

INVALID_PARAMETER_LENGTH

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

Maximum Spike Angle

Specify the maximum angle in degrees between two line segments to be considered a spike.

The value must be between 0 and 180 degrees.

Maximum Spike Length

Default: Blank.

Optionally specify a maximum length in ground units. Spike length is determined by the shorter side.

Spikes longer than this length will not be removed.

Dimension

Select which coordinates are to be used when determining spike angle and length:

  • 3D: Z coordinates are considered.
  • 2D: Z coordinates are ignored.

Remove Spikes Iteratively

Select a method of spike removal:

  • No: One end-to-end pass of spike removal is done and the Removed vertices receive attributes:
    • _spike_angle
    • _spike_length1
    • _spike_length2
  • Yes: Any new spikes created by spike removal are iteratively removed until none remain. Attributes are not added.

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

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.

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.

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.

Table Tools

Transformers with table-style parameters have additional tools for populating and manipulating values.

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.

For more information, see Transformer Parameter Menu Options.

Reference

Processing Behavior

Feature-Based

Feature Holding

No
Dependencies None
Aliases  
History  

FME Community

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