Extracts Ground Control Point (GCP) coordinate system and point values from a raster feature and exposes them as attributes.

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Typical Uses

  • Extracting GCP raster properties to an attribute for use elsewhere in a workspace.

How does it work?

The RasterGCPExtractor receives raster features and extracts any Ground Control Points (GCPs) that exist as a raster property on the input feature. The following attributes are added to the output features:

_gcp_coordsys The GCP coordinate system.

All existing GCPs, as a string.

Each GCP has five components, separated by spaces:

Column Row X-Coordinate Y-Coordinate Z-Coordinate

For example:

1442 6863 483000 5456000 0

Multiple GCPs are combined into one string, separated by semicolons:

1442 6863 483000 5456000 0;1415 1143 483000 5468000 0;4754 1120 490000 5468000 0

The GCPs are not removed from the raster properties, and so exist as both properties and attributes on the output features.

This transformer is unaffected by raster band and palette selection.


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).


Input Ports

Output Ports


This transformer has no parameters.

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

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

Contains information licensed under the Open Government Licence – Canada.