Densifier

Adds vertices to linear features at regular intervals.

Typical Uses

Preserving geometry shapes through reprojection
Adding vertices for more even feature chopping

How does it work?

The Densifier receives features with line or area geometry and adds additional vertices to them at regular intervals.

Spacing is specified in ground units, and the placement is guided by Mode:

Exact Interval: Vertices are added at the specified interval after each existing vertex.
Uniform Interval: Each segment of the feature is considered individually. The segment receives new vertices dividing it into equal parts. The number of parts is guided by the Interval value, and the distance between vertices can vary between segments.

	Settings	Result
Input Feature
Exact Interval
Uniform Interval

Examples

Example: Densifying linear features for reprojection

In this example, we have a set of polygons representing mapsheet boundaries across Canada. They are in a lat/long geographic coordinate system, and they are rectangles with points only at each corner.

Provincial boundaries are also displayed for reference.

We want to work in British Columbia, at the far west end, and so reproject to a suitable coordinate system for that area.

The straight edges of the polygons are still straight - which does not accurately represent where they fall in this UTM projection. The lines of latitude should curve.

The features are routed into a Densifier prior to reprojecting.

In the parameters dialog, an interval is set to add additional vertices along the feature. This is in ground units - in this case, degrees.

The reprojected feature is much more accurate.

The positional difference between a two-point line and the densified line can be substantial.

Usage Notes

To add a single vertex at a known position, use a VertexCreator.
Use an ArcStroker to densify arcs or arcs within paths.
The Generalizer may be useful for reversing densification.
To densify a raster, use a RasterResampler.

Configuration

Input Ports

Output Ports

Parameters

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.

How to Set Parameter Values

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.

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

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.