Generates a palette from the selected band(s) of a raster. The output raster will have the selected band(s) replaced by a new band with a palette.

Jump to Configuration

Typical Uses

  • Creating a palette based on raster contents for use elsewhere.
  • Reducing file size or bit depth on rasters to meet format or processing requirements.

How does it work?

The RasterPaletteGenerator receives raster features and builds a palette from the existing cell values. The output raster feature will have the selected band(s) replaced with a band with the resulting palette, and cell values replaced with palette key values.

The Palette Key Interpretation Type may be UInt8, UInt16, or UInt32, and both the new palette and band will have the chosen interpretation type. The number of palette keys generated can be automatically determined, or specified within the range of 16 to the maximum number of values supported by the interpretation type.

Key Interpretation Type

Key Value Range

Minimum Number of Keys

Maximum Number of Keys

UInt8 0 to 255 16 256
UInt16 0 to 65,535 16 65,536
UInt32 0 to 4,294,967,295 16 4,294,967,296

Valid palette types that may be produced include:

  • RGB24
  • RGB48
  • RGBA32
  • RGBA64
  • GRAY8
  • GRAY16

This operation may cause loss of precision if the maximum number of palette entries is less than the number of unique band values. In this case, the data values in the palette may not capture all the original band data values.

This transformer supports raster band selection. The RasterSelector can be used to modify 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


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.