RasterHillshader
Generates a grayscale shaded relief representation of terrain, based on elevation values.
Jump to Configuration
Typical Uses
- Visualizing terrain
- Generating hillshade texture for use as a background for other map data
How does it work?
The RasterHillshader receives elevation raster features and creates a shaded relief representation, derived from slope and aspect calculated on the input elevation values.
The input raster’s horizontal and vertical units are expected to be the same.
Input band(s) are converted to GRAY8, with hillshade values between 0 and 255. The position of the light source may be adjusted, and a choice of algorithms is available.
If the input band has a nodata value set, or if Interpolate Nodata is set to No, an ALPHA8 band is also generated, with a cell value of 0 (fully transparent) where the input was nodata and a value of 255 (fully opaque) where the input was data.
Interpolate Nodata means that nodata values will be replaced with actual values, calculated from the neighboring cells. When Interpolate Nodata is set to Yes, there are no nodata cells, and so no alpha band is required.
This transformer supports raster band selection. The RasterSelector can be used to modify this selection.
Z Factor, Scaling and Units
Input rasters’ horizontal (x and y) units are expected to be the same as vertical (z) units.
If this is not the case - for example, if the horizontal units are in meters with elevation (z) in feet (or any other similar unit type mismatch), you may apply a scale factor (also known as Z Factor) with the Scaler transformer prior to using a RasterHillshader.
In that example (ground units are meters, elevations are feet), the scale factor to use is 0.3048 - the number of meters in one foot.
If the ground units are decimal degrees (lat/long), the appropriate scale factor will vary greatly between the equator and the poles. In this case, consider reprojecting the input raster with a Reprojector, to an appropriate coordinate system with ground units matching the vertical (z) units.
If units are mismatched, the transformer may complete processing, but will produce incorrect or unexpected results.
Example: Creating a hillshade from elevation data
In this example, we will generate a hillshade representation of a Digital Elevation Model (DEM). The source data ranges in elevation from sea level (0) to around 1500 meters, in a mountainous area.
Note that elevation is stored in Band 0, as 32-bit integer, and that it does have a Nodata Value set.
Note: This format, CDED, is in an LL83-SECONDS coordinate system - and so the lat/long horizontal (ground) units do not match the vertical (elevation) units in meters.
The DEM is routed first into a Reprojector, where it is converted to UTM83-10, an appropriate local coordinate system with ground units in meters, matching the elevation value units. Then it is routed into a RasterHillshader.
In the parameters dialog, we will keep the default settings. They include the light source’s Azimuth of 315 degrees and Altitude of 45 degrees, which are commonly used values. Interpolate Nodata is set to Yes, and the Algorithm is Horn.
The output raster has two bands. Hillshade values (0 to 255) are in the GRAY8 band. The ALPHA8 band represents the nodata values of the original elevation raster.
Note the shape of the output raster compared to the original DEM data - a result of the reprojection.
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 combing 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.
| RasterCellOriginSetter
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Sets the cell origin point within cells in a raster.
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| RasterConvolver
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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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| RasterExpressionEvaluator
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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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| RasterExtentsCoercer
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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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| RasterGCPExtractor
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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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| RasterGCPSetter
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Sets Ground Control Points (GCPs) on a raster, pairing cell positions with known coordinates.
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| RasterGeoreferencer
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Georeferences a raster by either known corner coordinates or origin, cell size, and rotation.
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| RasterHillshader
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Generates a grayscale shaded relief representation of terrain, based on elevation values.
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| RasterInterpretationCoercer
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Alters the interpretation type of rasters, including all bands, and converts cell values if necessary.
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| RasterMosaicker
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Merges multiple raster features into a single raster feature.
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| RasterPropertyExtractor
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Extracts the geometry properties of a raster feature and exposes them as attributes.
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| RasterPyramider
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Resamples rasters to multiple resolutions, based on either number of levels or dimensions of the smallest output raster. |
| RasterResampler
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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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| RasterRotationApplier
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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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| RasterSubsetter
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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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| RasterTiler
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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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| RasterToPolygonCoercer
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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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| WebMapTiler
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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.
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Working with Bands
Working with Cells
Working with Palettes
Workflow Control
These transformers generally control the flow of features in a workspace.
| RasterCheckpointer
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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. |
| RasterConsumer
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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. |
| RasterExtractor
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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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| RasterNumericCreator
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Creates a numeric raster of specified size and resolution, with default cell values.
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| RasterReplacer
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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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| RasterRGBCreator
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Creates a color raster feature of specified size, resolution, and interpretation type, with default cell values.
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| RasterSelector
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Selects specific bands and palettes of a raster for subsequent transformer operations.
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Vectors and Rasters
These transformers generally involve using rasters and vector data together.
| ImageRasterizer
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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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| NumericRasterizer
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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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| MapnikRasterizer
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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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| PointOnRasterValueExtractor
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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. |
| RasterDEMGenerator
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Produces a raster digital elevation model (DEM) by uniformly sampling a Delaunay triangulation generated from input points and breaklines. |
| VectorOnRasterOverlayer
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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.
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Configuration
Input Ports
Input
Raster features with elevation values. For best results the horizontal (x and y) units should be the same as the vertical (z) units.
Output Ports
Output
Raster features with hillshade values in GRAY8 bands. ALPHA8 bands will also be present if input raster features have a nodata value, or if Interpolate Nodata is set to No.
<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_CANNOT_HILLSHADE
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
Parameters
| Azimuth
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Azimuth angle of the light source, expressed in positive degrees from 0 to 360, measured clockwise from north.
The default value, 315 (northwest), is commonly used to generate shaded maps.
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| Altitude
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Altitude angle of the light source above the horizon, expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly overhead.
The default value, 45, is commonly used to generate shaded maps.
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| Interpolate Nodata
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Calculate values at raster edges and near nodata values.
No: When any pixel in the 3x3 window used to calculate the hillshade value is equal to nodata, the output pixel will also be set to nodata. If the input band does not have a nodata value, the output band nodata value will be set to -1. There will be a one pixel border around the edge of the raster set to the nodata value.
Yes: Values around the edge and near nodata values will be estimated by interpolating missing values. Note that holes will not be filled in - cells that are nodata in the input raster will remain nodata in the output.
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| Algorithm
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The algorithm used to calculate slope and aspect. Some analyses have suggested that Horn's formula is better suited to rougher terrain, whereas Zevenbergen & Thorne's formula is better for smooth terrain.
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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.
Text Editor
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.
Arithmetic Editor
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 - whether entered directly in a parameter or constructed using one of the editors.
Reference
FME Community
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Search for all results about the RasterInterpretationCoercer on the FME Community.
Examples may contain information licensed under the Open Government Licence – Vancouver