Outputs circular sectors of influence for point features that have directions defined by azimuths (degrees clockwise from North).

This transformer creates a number of sectors for each set of point features (collectively called a site), depending on each point’s direction of influence. Each sector fans out from the center point (site point) of the site it belongs to, and has a user-defined radius.

This transformer generates a Voronoi diagram that consists of polygons representing the closest areas around center points of sectors (site points). The final output will be the sectors truncated to the extents of their site’s corresponding Voronoi polygons.

This transformer has an additional output port that produces sectors truncated by Voronoi polygons, to eliminate possible overlaps between different sites.

Note: To create sectors that may overlap with sectors of other sites, use the SectorGenerator transformer instead.


In the telecommunications industry, directional antennas are used in conjunction with each other for better coverage and stronger signal reception. These antennas each cover a sector of a complete circle that an antenna tower covers, with some areas of overlap between each two sectors.

This transformer can be used to determine the “Nominal” (assuming a whole circle is covered and there are no overlaps between any two sectors) coverage field of directional antennas and receivers.

Input points and their azimuth values are received:

A center point is created for each site:

Note: Please note that after this step, the locations of input points play no part in the generation of sectors, and the values that determine sectors are the input points’ azimuths and radii.

Polygon sectors are generated. The sector corresponding to each point will span an area determined by the radius set and:

(The point's azimuth + adjacent azimuth (in degrees))/2

Two sides of a sector are found by one time choosing the closest azimuth clockwise and the next time counter-clockwise. Resulting sectors will look like this:

Voronoi polygons are generated, based on site points:

If two sites have overlapping sectors, the sectors are clipped by the Voronoi polygons to generate Cells:


Input Ports

Output Ports


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.

Dialog Options - Tables

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

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for samples and information about this transformer on the FME Community.