BoundingBoxReplacer

Replaces feature geometry with a box or cube that spans the extents of the feature.

Typical Uses

Determining the extents of individual features

How does it work?

The BoundingBoxReplacer receives features with any geometry type and individually replaces their geometry with one of:

2D Bounding Box - the minimum enclosing rectangle, with sides parallel to the x and y axes.
2D Oriented Bounding Box - rotated to fit the feature as tightly as possible while remaining a rectangle.
3D Bounding Cube - the minimum enclosing cube for 3D features, including point clouds. The cube is axis-aligned.

Requesting 2D bounding boxes for 3D features produces footprints. Requesting a 3D bounding cube for a 2D feature produces a 2D box.

If an output bounding box or cube has zero area (if the input feature is a single point or vertical line, for example), it will become a point or line as appropriate.

Feature attributes are retained.

Examples

Example: Bounding boxes for linear features

In this example, we will generate two types of 2D bounding boxes for a set of transit line features.

Note that there are three features, with an attribute containing their name.

The features are routed into a BoundingBoxReplacer.

2D Bounding Boxes

In the parameters dialog, Replace With is set to 2D Bounding Box.

Note that attributes can be created for the bounding box side lengths, but they are not added by default.

The output features have had their geometry replaced by bounding boxes, and the attributes remain intact.

2D Oriented Bounding Boxes

When Replace With is set to 2D Oriented Bounding Box, an additional attribute is enabled to extract the oriented box’s angle.

We supply attribute names for all three.

The output features have their geometry replaced by oriented rectangular bounding boxes.

Their original attributes are intact, with new attributes added containing side lengths and rotation angles.

Usage Notes

Creating Boxes and Rectangles

Creating rectangular geometry is a common task. These transformers do so in a variety of ways.

Transformer	Function
Creator	Creates one or more new features with box geometry of a specific size and position (when Geometry Object is Box).
2DBoxReplacer	Replaces an existing feature’s geometry with a box of a specific size and position.
BoundingBoxAccumulator	Creates one rectangle that encompasses all features received.
BoundingBoxReplacer	Individually replaces the geometry of each feature with a rectangle that covers its extents.
RasterExtentsCoercer	Individually replaces the geometry of each raster feature with a rectangle that covers its extents (with various Extents Type options).
BoundsExtractor	Extracts the coordinate values that describe an individual feature’s bounding box (or cube) and stores them as attributes.
2DGridAccumulator	Creates a series of regularly-spaced rectangles that span the extent of all features received (when Type of Grid to Create is Polygons).
2DGridCreator	Creates a series of regularly-spaced rectangles of a specific size and position (when Type of Grid to Create is Polygons).
Tiler and RasterTiler	Do not create actual rectangles, but chop features into a series of rectangular tiles, specified in a similar fashion to the 2DGridAccumulator.

Configuration

Input Ports

Output Ports

Parameters

Output Attribute Names

Long Side Length

Name the attribute to contain the length of the longest side of the bounding box or cube, in ground units.

Short Side Length

Name the attribute to contain the length of the shortest side of the bounding box or cube, in ground units.

Long Side Angle

When Replace With is 2D Oriented Bounding Box, name the attribute to contain the angle of the longest side of the bounding box.

The angle is measured counter-clockwise from the positive x axis with values between 0 and 180 degrees.

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.

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

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

Table Tools

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.

Reference

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

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