RasterCellValueReplacer

Replaces ranges of band values in a raster with single values.

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Typical Uses

  • Classifying cell value ranges
  • Adjusting image threshold

How does it work?

The RasterCellValueReplacer receives raster features. Each band value of each cell is compared to a defined set of numeric ranges, and values that match a range definition are replaced with a new, single defined value.

Ranges are defined in a Range Table, using From and To parameters, which may be combined in a variety of ways. If both parameters are defined, both are applied. These examples assume that the band values are integers.

Example

From (>=)

To (<=)

Find values from 10 to 20 , inclusive

10

20

Find the single value 45

45

45

Everything except the value 45

46

44

Find values less than 100

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99

Find values of 50 or greater

50

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Find two distinct ranges at the upper and lower limits, values 50 and below, and values more than 99 (everything outside a range)

99

50

Replace all values

0

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The new value may be defined as a single value, or as an expression.

For multi-band rasters, each band is processed identically on every cell, comparing the individual band values to the defined range(s). For example, if the range is <= 100, with a replacement value of 25, an RGB value of 14,87,192 becomes 25,25,192. To restrict operation to specific band(s), use a RasterSelector prior to the RasterCellValueReplacer.

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

Examples

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).

Configuration

Input Ports

Output Ports

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.

Reference

Processing Behavior

Feature-Based

Feature Holding

No

Dependencies None
Aliases  
History  

FME Community

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