Replaces the geometry of input raster features with a polygon covering either the extents of a raster or the extent of data within a raster.

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Typical Uses

  • Creating polygon raster footprints for indexing or processing efficiency
  • Identifying areas with or without data within a raster.
  • Creating a clip boundary for use on other data

How does it work?

The RasterExtentsCoercer receives raster features and creates one polygon per raster that covers one of the following:

  • Raster Extents: The extent of the entire raster, as a rectangle, which may be rotated.
  • Data MBR Extents: The minimum bounding rectangle containing all cells with valid data (that is, do not have the Nodata value).
  • Data Extents: The exact footprint of all cells with valid data within the raster, which may produce non-rectangular polygons, and may produce an aggregate polygon with multiple parts per raster feature.

The selected extents polygons are output, and the input raster features are discarded. Output polygons retain original raster attributes, including fme_basename and fme_dataset.

This transformer supports raster band selection. Palettes are unaffected.


Usage Notes

Choosing a Raster Transformer

FME has an extensive selection of transformers for working with raster data. They can be generally categorized as working with whole rasters, bands, cells or palettes, and those designed for workflow control or combining raster with vector data.

For information on raster geometry and properties, see Rasters (IFMERaster).

Creating Boxes and Rectangles

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




Creates one or more new features with box geometry of a specific size and position (when Geometry Object is Box).


Replaces an existing feature’s geometry with a box of a specific size and position.


Creates one rectangle that encompasses all features received.


Individually replaces the geometry of each feature with a rectangle that covers its extents.


Individually replaces the geometry of each raster feature with a rectangle that covers its extents (with various Extents Type options).


Extracts the coordinate values that describe an individual feature’s bounding box (or cube) and stores them as attributes.


Creates a series of regularly-spaced rectangles that span the extent of all features received (when Type of Grid to Create is Polygons).


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.


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.


Processing Behavior


Feature Holding


Dependencies None

FME Community

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