Reads raster features for testing purposes, including any accumulated raster operations. No additional operations are performed, and nothing is done with the features.
Typical Uses
- Performance testing or benchmarking raster processing.
- Debugging raster processing.
- Testing raster feature validity.
How does it work?
The RasterConsumer receives raster features and reads all of their data at their current state in the workspace. It does not perform any new operations on the rasters.
FME handles rasters in a “delayed evaluation” model. A raster reader reads essential information about a raster, but does not read the actual cell contents until it is absolutely necessary. Transformer operations are accumulated until the results are needed, often being held until the features enter a writer. At that point, the required data is fully read and processed.
This is intended to optimize performance - for example, if a raster is both clipped and reprojected, FME will optimize processing by not reprojecting data that falls outside of the clip boundary and is ultimately discarded.
The RasterConsumer transformer forces this read to occur, and any accumulated operations are performed as the features are read. Nothing is done with the read features, and the transformer will not improve performance - it simply emulates the effect that reading the data would have, wherever it is placed.
It can be used to test workspace performance without configuring writers, and can also be useful for debugging raster processing workspaces with multiple accumulated operations. It may also be used for raster geometry validation, as it will reject any non-raster features.
This transformer is unaffected by raster band and palette selection.
Note: Though the transformer has parameters that can be used to adjust the way in which the raster is read (tiles), they are primarily of interest for internal Safe performance testing and are not generally useful in a production environment.
Examples
Example: Estimating raster processing time
In this example, we are building a raster processing workspace.
The source dataset is a 2 Gb GeoTIFF raster, which needs to be reprojected, then pyramided, and then passed along for further processing.
As both of these operations will be accumulated until they are required (such as enter a writer), we cannot yet determine how long it might take to process this.
A run of the workspace as it stands is very fast, an indication that the two raster operations have been held for later processing.
To get a more accurate idea of how long this will take, we add a RasterConsumer after the two raster processing transformers - the Reprojector and RasterPyramider.
In the parameters dialog, we keep the default settings.
Running the workspace again, we can see that it will take significantly more time to fully read and process the rasters, with the accumulated operations applied.
Usage Notes
- The RasterCheckpointer similarly forces processing of any accumulated raster operations, but also writes the current state to a temporary disk file. It may be placed between raster transformers to potentially optimize processing performance and memory usage.
- The Enable Feature Caching option in FME Workbench should be disabled to obtain more accurate processing benchmarks.
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).
Raster Transformers
Working with Rasters
These transformers generally apply to whole rasters.
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Sets the cell origin point within cells in a raster. |
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Applies a convolution filter (sometimes called a kernel or lens) to raster features and outputs the results. |
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Evaluates expressions on each cell in a raster or pair of rasters, including algebraic operations and conditional statements. |
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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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Extracts Ground Control Point (GCP) coordinate system and point values from a raster feature and exposes them as attributes. |
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Sets Ground Control Points (GCPs) on a raster, pairing cell positions with known coordinates. |
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Georeferences a raster by either known corner coordinates or origin, cell size, and rotation. |
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Generates a grayscale shaded relief representation of terrain, based on elevation values. |
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Alters the interpretation type of rasters, including all bands, and converts cell values if necessary. |
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Merges multiple raster features into a single raster feature. |
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Extracts the geometry properties of a raster feature and exposes them as attributes. |
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Resamples rasters to multiple resolutions, based on either number of levels or dimensions of the smallest output raster. |
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Transforms an image to minimize its difference with another. |
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Resamples rasters, based on specified output dimensions, cell size in ground units, or percentage of original, and interpolates new cell values. |
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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. |
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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. |
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Clips raster features using pixel bounds instead of ground coordinates, and optionally adds cells around the perimeter. |
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Splits each input raster into a series of tiles by specifying either a tile size in cells/pixels or the number of tiles. |
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Creates polygons from input raster features. One polygon is output for each contiguous area of pixels with the same value in the input raster. |
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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
These transformers generally apply to bands.
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Adds a new band to a raster feature. |
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Merges coincidental raster features into a single output raster feature, preserving and appending all bands. |
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Alters the interpretation type of individual raster bands, converting cell values if necessary. |
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Removes all unselected bands from a raster feature. |
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Extracts the minimum and maximum band values, palette keys, and palette values from a raster feature, and adds them to a list attribute. |
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Sets the band name of selected bands on a raster, making raster contents simpler to understand compared to band numbers. |
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Removes the existing Nodata identifier from selected bands of a raster feature. Any values previously equal to the Nodata value are considered valid data. |
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Sets a new Nodata value on selected bands of a raster feature. |
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Specifies the required order of bands in a raster. Bands are reordered according to the input band indices. |
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Extracts the band and palette properties of a raster feature and exposes them as attributes. |
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Removes any selected bands from a raster feature. |
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Separates bands or unique band and palette combinations, and outputs either individual raster features or a single new raster feature containing all combinations. |
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Calculates statistics on raster bands and adds the results as attributes. |
Working with Cells
These transformers generally apply to individual cells.
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Calculates the aspect (direction of slope) for each cell of a raster. Aspect is measured in degrees from 0 to 360, clockwise from north. |
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Creates individual points or polygons for each cell in a raster, optionally extracting band values as z coordinates or attributes. |
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Evaluates basic arithmetic , minimum, maximum or average operations on the cell values of a pair of rasters. |
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Replaces a range of band values in a raster with a new single value. |
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Rounds off raster cell values. |
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Partitions a raster image into arbitrarily sized groups of cells from the input image based on intensity differences in the input raster image cells. |
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Performs basic arithmetic operations on the cell values of a raster against a numeric value. |
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Calculates the slope (maximum rate of change in z) for each cell of a raster. |
Working with Palettes
These transformers generally apply to palettes.
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Creates a palette from an attribute, and adds this palette to all selected bands on a raster. |
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Creates a string representation of an existing palette on a raster and saves it to an attribute. |
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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. |
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Alters the interpretation type of raster palettes. |
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Identifies the palette key that matches a raster band’s Nodata value, and sets a value on it. |
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Removes selected palette(s) from raster features. |
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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. |
Workflow Control
These transformers generally control the flow of features in a workspace.
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Forces accumulated raster operations to be processed, saving the state to disk and releasing resources to tune performance or assist with memory limitations. |
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Reads raster features for testing purposes, including any accumulated raster operations. No additional operations are performed, and nothing is done with the features. |
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Serializes the geometry of a raster feature into a Blob attribute, encoding the contents according to a choice of common binary raster formats. |
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Creates a numeric raster of specified size and resolution, with default cell values. |
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Decodes a binary attribute containing encoded rasters stored as Blobs, replacing the feature’s geometry with the decoded raster. |
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Creates a color raster feature of specified size, resolution, and interpretation type, with default cell values. |
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Selects specific bands and palettes of a raster for subsequent transformer operations. |
Vectors and Rasters
These transformers generally involve using rasters and vector data together.
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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. |
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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. |
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Generates a raster from input vector and raster features, with fine control over symbolization and labeling, using the Mapnik toolkit. |
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Sets point cloud component values by overlaying a point cloud on a raster. The component values for each point are interpolated from band values at the point location. |
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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. |
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Produces a raster digital elevation model (DEM) by uniformly sampling a Delaunay triangulation generated from input points and breaklines. |
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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. |
Configuration
Input Ports
Input
This transformer accepts only raster features.
Output Ports
Output
Raster features with no modifications made.
<Rejected>
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:
INVALID_GEOMETRY_TYPE
INVALID_RASTER_NO_BANDS
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.
Parameters
Note that the default parameter settings are generally used.
Request Pattern
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Tile Request Order |
Tile (Default): The raster data is read one tile at a time until all tiles are consumed. Several bands may be read for a given tile. Band: The raster data is read one band at a time until all bands are consumed. |
Tile Size
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Tile Size |
Use source tile size (Default): The default tile size reported by the band will be used when tiles or bands are consumed. Specify source tile size: The raster will be consumed using the specified Number of Tile Rows and Number of Tile Columns. |
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Number of Tile Rows
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In conjunction with Specify source tile size, specify the number of rows and columns. |
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.
How to Set Parameter Values
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.
Conditional Values
Set values depending on one or more test conditions that either pass or fail.
Parameter Condition Definition Dialog
Content
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.
Content Types
| These functions manipulate and format strings. | |
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Special Characters |
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. |
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Table Tools
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Row Reordering
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Enabled once you have clicked on a row item. Choices include:
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Cut, Copy, and Paste
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Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers. |
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Filter
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Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output. |
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Import
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Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers. |
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Reset/Refresh
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Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers. |
Note: Not all tools are available in all transformers.
Reference
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Processing Behavior |
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Feature Holding |
No |
| Dependencies | None |
| Aliases | |
| History |
FME Community
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Search for all results about the RasterConsumer on the FME Community.
Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.