RasterHillshader

Generates a grayscale shaded relief representation of terrain, based on elevation values.

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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.

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).

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.

Reference

Processing Behavior

Feature-Based

Feature Holding

No

Dependencies None
FME Licensing Level FME Professional Edition and above
Aliases  
History  
Categories

3D

Cartography and Reports

Rasters

FME Community

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Examples may contain information licensed under the Open Government Licence – Vancouver