Alters the interpretation type of individual raster bands, converting cell values if necessary.
- Changing individual raster band interpretation to meet processing or format requirements
How does it work?
The RasterBandInterpretationCoercer receives raster features and converts all or selected bands to one chosen Destination Interpretation Type.
Options are available to control the manner in which cell values are converted, handling color to color, numeric to color, color to numeric, numeric to numeric, and floating point to integer conversions.
Band names, if they exist, are retained.
If bands selected for conversion contain palettes, the destination interpretation is restricted to UInt8, UInt16 or UInt32.
To select specific bands, use the RasterSelector prior to the RasterBandInterpretationCoercer.
In this example, we will convert a single-band numeric raster to gray. The source raster is a GeoTIFF, with cell values ranging from 0 to 10, representing different land zoning. Note that the raster contains one band, and the interpretation type is INT8 - an 8-bit integer.
The Data Inspector knows the value range, and displays the cells as shades of gray, where 0 is black and 10 is white.
However, viewing the raster in another image viewer shows a nearly solid black image, because the values (maximum 10), when interpreted against a range of 0 to 255, are close to zero.
In order to use the raster for presentation purposes, it needs to be converted to a proper gray scale.
The raster is routed into a RasterBandInterpretationCoercer.
In the parameters dialog, we set the Destination Interpretation Type to Gray8. Three Conversion Options are enabled (as the transformer does not know what type of band will be received).
The important one for this translation is Convert from Numeric to Color. We choose Scale by data values, which will take the source range (0 to 10), and scale the values according to the destination type range (0 to 255).
The output raster feature contains a single band, and the Interpretation Type is now GRAY8. Note the cell value selected, previously 8, is now 204.
- The RasterInterpretationCoercer performs similar operations on the raster as a whole, such as converting 4 bands directly to RGBA.
- The RasterPaletteInterpretationCoercer performs similar conversions on palettes.
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).
Working with Rasters
|RasterCellOriginSetter||Sets the cell origin point within cells in a raster.|
Applies a convolution filter (sometimes called a kernel or lens) to raster features and outputs the results.
|RasterExpressionEvaluator||Evaluates expressions on each cell in a raster or pair of rasters, including algebraic operations and conditional statements.|
|RasterExtentsCoercer||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.|
|RasterGCPExtractor||Extracts Ground Control Point (GCP) coordinate system and point values from a raster feature and exposes them as attributes.|
|RasterGCPSetter||Sets Ground Control Points (GCPs) on a raster, pairing cell positions with known coordinates.|
|RasterGeoreferencer||Georeferences a raster by either known corner coordinates or origin, cell size, and rotation.|
|RasterHillshader||Generates a grayscale shaded relief representation of terrain, based on elevation values.|
Alters the interpretation type of rasters, including all bands, and converts cell values if necessary.
|RasterMosaicker||Merges multiple raster features into a single raster feature.|
|RasterPropertyExtractor||Extracts the geometry properties of a raster feature and exposes them as attributes.|
|RasterPyramider||Resamples rasters to multiple resolutions, based on either number of levels or dimensions of the smallest output raster.|
|RasterRegisterer||Transforms an image to minimize its difference with another.|
|RasterResampler||Resamples rasters, based on specified output dimensions, cell size in ground units, or percentage of original, and interpolates new cell values.|
Rotates a raster feature according to its rotation angle property, interpolating new cell values, updating all other affected raster properties, and producing an output raster feature with a rotation angle of zero.
|RasterSharpener||Enhances the features of a raster image. The RasterSharpener enhances the borders, lines, and curves while reducing noise in the flat areas of the raster image.|
|RasterSubsetter||Clips raster features using pixel bounds instead of ground coordinates, and optionally adds cells around the perimeter.|
|RasterTiler||Splits each input raster into a series of tiles by specifying either a tile size in cells/pixels or the number of tiles.|
|RasterToPolygonCoercer||Creates polygons from input raster features. One polygon is output for each contiguous area of pixels with the same value in the input raster.|
|WebMapTiler||Creates a series of image tiles that can be utilized by web mapping applications such as Bing™ Maps, Google Maps™, or Web Map Tile Service. This is done by resampling rasters to various different resolutions and then splitting them into tiles.|
Working with Bands
|RasterBandAdder||Adds a new band to a raster feature.|
|RasterBandCombiner||Merges coincidental raster features into a single output raster feature, preserving and appending all bands.|
Alters the interpretation type of individual raster bands, converting cell values if necessary.
Removes all unselected bands from a raster feature.
|RasterBandMinMaxExtractor||Extracts the minimum and maximum band values, palette keys, and palette values from a raster feature, and adds them to a list attribute.|
|RasterBandNameSetter||Sets the band name of selected bands on a raster, making raster contents simpler to understand compared to band numbers.|
|RasterBandNodataRemover||Removes the existing nodata identifier from selected bands of a raster feature. Any values previously equal to the nodata value are considered valid data.|
|RasterBandNodataSetter||Sets a new nodata value on selected bands of a raster feature.|
|RasterBandOrderer||Specifies the required order of bands in a raster. Bands are reordered according to the input band indices.|
|RasterBandPropertyExtractor||Extracts the band and palette properties of a raster feature and exposes them as attributes.|
|RasterBandRemover||Removes any selected bands from a raster feature.|
|RasterBandSeparator||Separates bands or unique band and palette combinations, and outputs either individual raster features or a single new raster feature containing all combinations.|
|RasterStatisticsCalculator||Calculates statistics on raster bands and adds the results as attributes.|
Working with Cells
Calculates the aspect (direction of slope) for each cell of a raster. Aspect is measured in degrees from 0 to 360, clockwise from north.
|RasterCellCoercer||Creates individual points or polygons for each cell in a raster, optionally extracting band values as z coordinates or attributes.|
|RasterCellValueCalculator||Evaluates basic arithmetic , minimum, maximum or average operations on the cell values of a pair of rasters.|
|RasterCellValueReplacer||Replaces a range of band values in a raster with a new single value.|
|RasterCellValueRounder||Rounds off raster cell values.|
|RasterSegmenter||Partitions a raster image into arbitrarily sized groups of cells from the input image based on intensity differences in the input raster image cells.|
|RasterSingularCellValueCalculator||Performs basic arithmetic operations on the cell values of a raster against a numeric value.|
|RasterSlopeCalculator||Calculates the slope (maximum rate of change in z) for each cell of a raster.|
Working with Palettes
Creates a palette from an attribute, and adds this palette to all selected bands on a raster.
|RasterPaletteExtractor||Creates a string representation of an existing palette on a raster and saves it to an attribute.|
|RasterPaletteGenerator||Generates a palette out of the selected band(s) of a raster. The output raster will have the selected band(s) replaced by a new band with a palette.|
Alters the interpretation type of raster palettes.
Identifies the palette key that matches a raster band’s nodata value, and sets a value on it.
|RasterPaletteRemover||Removes selected palette(s) from raster features.|
|RasterPaletteResolver||Resolves the palette(s) on a raster by replacing cell values with their corresponding palette values. Palette values with multiple components, such as RGB, are broken down and the individual values assigned to multiple, newly-added bands.|
|RasterCheckpointer||Forces accumulated raster operations to be processed, saving the state to disk and releasing resources to tune performance or assist with memory limitations.|
|RasterConsumer||Reads raster features for testing purposes, including any accumulated raster operations. No additional operations are performed, and nothing is done with the features.|
|RasterExtractor||Serializes the geometry of a raster feature into a Blob attribute, encoding the contents according to a choice of common binary raster formats.|
|RasterNumericCreator||Creates a numeric raster of specified size and resolution, with default cell values.|
|RasterReplacer||Decodes a binary attribute containing encoded rasters stored as Blobs, replacing the feature’s geometry with the decoded raster.|
|RasterRGBCreator||Creates a color raster feature of specified size, resolution, and interpretation type, with default cell values.|
Selects specific bands and palettes of a raster for subsequent transformer operations.
Vectors and Rasters
|ImageRasterizer||Creates a raster representation of vector or point cloud input features, using the fme_color attribute over a solid background fill for vector features. Point clouds may be rendered using their color or intensity components.|
|NumericRasterizer||Creates a numeric raster representation of vector or point cloud input features, where cell values are taken from the z coordinates of the input features and overlaid on a uniform background.|
|MapnikRasterizer||Generates a raster from input vector and raster features, with fine control over symbolization and labeling, using the Mapnik toolkit.|
|PointOnRasterValueExtractor||Extracts the band and palette values from a raster at the location of one or more input points and sets them as attributes on the feature.|
|RasterDEMGenerator||Produces a raster digital elevation model (DEM) by uniformly sampling a Delaunay triangulation generated from input points and breaklines.|
|VectorOnRasterOverlayer||Rasterizes vector or point cloud features onto an existing raster. For vector features the fme_color attribute sets pixel color, and point clouds may be rendered using their color or intensity components.|
This transformer accepts only raster features.
Raster features with bands modified as specified.
Non-raster features will be routed to the <Rejected> port, as well as invalid rasters.
Rejected features will have an fme_rejection_code attribute with one of the following values:
Rejected Feature Handling: can be set to either terminate the translation or continue running when it encounters a rejected feature. This setting is available both as a default FME option and as a workspace parameter.
|Destination Interpretation Type||Select the destination interpretation along with the bit depth. Different interpretations allow for different conversion options to be used.|
Convert from Color to Color
Convert from Numeric to Color
Convert from Color to Numeric
Convert from Numeric to Numeric
Select the action to undertake when the given conversion between different types occurs.
|Convert from Float to Integer||
Specifies the action to perform when converting from a floating-point value to an integer.
* Note: Cast and Bounded Cast use C-style casts.
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.
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.
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.
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.
Set values depending on one or more test conditions that either pass or fail.
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.
|These functions manipulate and format strings.|
|A set of control characters is available in the Text Editor.|
|Math functions are available in both editors.|
|Date/Time Functions||Date and time functions are available in the Text Editor.|
|These operators are available in the Arithmetic Editor.|
|These return primarily feature-specific values.|
|FME and workspace-specific parameters may be used.|
|Creating and Modifying User Parameters||Create your own editable parameters.|
|FME Licensing Level||FME Professional Edition and above|
|History||This transformer replaces the RasterDataTypeCoercer and RasterColorModelCoercer transformers.|
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Examples may contain information licensed under the Open Government Licence – Vancouver