CenterPointExtractor

Extracts the coordinates of a point located within the feature, its bounding box, or at its center of mass, and stores them as attributes.

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Typical Uses

Identifying the center of mass of a feature
Identifying the center of the bounding box of a feature
Identifying locations for annotation

How does it work?

The CenterPointExtractor receives features with any type of geometry and calculates a center point for each feature, according to a choice of Point Extraction Mode. The calculated coordinates are added to the feature as attribute values. Both 2D and 3D geometry are supported.

Aggregates are also supported, with one center point extracted for each aggregate.

Point Placement

The result of each center mode is shown below.

Original areas and their bounding boxes are included for reference.

Mode	Description	Result
	Input Features: Park polygons with their bounding boxes shown in blue.
Center Point of Bounding Box	Points are placed at the center of the feature’s bounding box. Point may fall outside the polygon.
Center of Gravity Point	Points are placed at the center of mass of the feature. Point may fall outside the polygon.
Any Inside Point	Points are placed at an arbitrary location inside the polygon.

Examples

Example: Extracting center point coordinates for a polygon

Usage Notes

This transformer does not alter geometry. To replace a feature with its center point, use a CenterPointReplacer.

Creating and Modifying Point and Text Features

These transformers work with points, text, and labels in a variety of ways.

Points and Text Transformers Comparison

Transformer	Use this to...	Transformer Description
Creator	Create one or more new features with box geometry of a specific size and position (when Geometry Object is Point or Text).	Creates features using the parameters supplied, and sends them into the workspace for processing.
VertexCreator	Replace a feature’s geometry with a point at a specified location.	Creates a single vertex to replace, be appended to, or be inserted into existing geometry.
CenterPointReplacer	Create points inside features or their bounding boxes.	Replaces feature geometry with a point located within the feature, its bounding box, or at its center of mass.
CenterPointExtractor	Extract the coordinates of a calculated point within the feature.	Extracts the coordinates of a point located within the feature, its bounding box, or at its center of mass, and stores them as attributes.
2DGridCreator	Create new regularly-spaced points in a specified location.	Creates a regular grid of points or rectangular polygons of a specified size, position, and coordinate system.
2DGridAccumulator	Create new regularly-spaced points over the extents of other features.	Creates a regular grid of points or rectangular polygons that span the extents of all input features.
Chopper	Create points from every vertex of input line or area geometry.	Chops line, arc, path, or area features into smaller features based on number of vertices or approximate length.
Intersector	Create points where features intersect.	Computes intersections between all input features, breaking lines and polygons wherever an intersection occurs and creating nodes at those locations.
PointCloudToPointCoercer	Create points from point cloud features.	Converts point clouds to point or multipoint geometries, optionally retaining attribute and component values.
Labeller	Label lines.	Places labels along a linear feature, angled to the orientation of each labeled segment.
TextAdder	Label points at an angle.	Replaces any geometry with a single text label at the center of its bounding box.
LabelPointReplacer	Label points and areas.	Replaces point, line, or area geometry with a single text label.
TextLocationExtractor	Convert text to geometry.	Replaces text with its location geometry, usually a point.
TextPropertyExtractor	Extract text properties into attributes.	Retrieves text property values from text geometry, adding them to the feature as attributes.
TextPropertySetter	Set or modify text properties.	Modifies or creates text geometry according to new coordinates, text string, size, or rotation values.
TextStroker	Convert text to non-text geometry.	Converts text to aggregate line or area geometry according to a specific True Type font.
PointPropertyExtractor	Extract point properties into attributes.	Extracts point orientation to feature attributes.
PointPropertySetter	Set or modify point properties.	Adds or removes point orientation.

Labelling and Geometry

Geometry	Recommended Transformer	Example
Point	LabelPointReplacer or TextAdder
Line	Labeller
Area	LabelPointReplacer

Configuration

Input Ports

Output Port

Parameters

Output Attribute Names

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

Dialog Options - Tables

For more information, see Transformer Parameter Menu Options.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies	None
Aliases	InsidePointExtractor
History

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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.

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.

X	Name the attribute to contain the x coordinate value of the center point.
Y	Name the attribute to contain the y coordinate value of the center point.
Z	Name the attribute to contain the z coordinate value of the center point.