Produces a raster digital elevation model (DEM) by uniformly sampling a Delaunay triangulation generated from input points and breaklines.

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Typical Uses

  • Creating raster elevation models from non-gridded features such as contours or point clouds.

How does it work?

The RasterDEMGenerator receives input features, triangulates a surface based on them, and then outputs a raster DEM with elevation values sampled from the surface at a specified regular interval. The output raster will contain a single numeric band, of the interpretation type Real64.

The input features are discarded.

Input features can be of a variety of types, including points, lines, areas, rasters, and point clouds. Aggregate geometries are supported, and multiple input features and types may be combined to produce one raster DEM output feature.

There are two input ports - Points/Lines and Breaklines. At least one input feature must be provided, which may be routed into either of these ports.

Input features may be either 2D or 3D - however, 2D features will be forced to 3D with an elevation (z value) of zero (0). If the source dataset’s z values are not stored as z coordinates (for example, contours with elevation stored as an attribute), a 3DForcer transformer may be used to convert them to a z coordinate prior to entering the RasterDEMGenerator.

A choice of interpolation methods is available. Surface tolerance and cell spacing may be adjusted, and a Nodata value may be defined.

This transformer is unaffected by raster band and palette selection.


Usage Notes

  • If input features’ elevation values are not stored as Z coordinates, use a 3DForcer prior to the RasterDEMGenerator.
  • To produce individual elevation points instead of a raster, consider using the DEMGenerator.
  • To build a TIN (triangulated irregular network) surface from points, lines, and/or rasters, see the TINGenerator and SurfaceModeller.

  • When processing large input datasets, increasing the Surface Tolerance may provide performance gains, but may reduce accuracy.
  • For more complex elevation modelling tasks, such as including contour generation, accessing components of the underlying surface model, feature draping, or creating multiple representations of a surface model, consider using the SurfaceModeller.

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).


Input Ports

Output Ports


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.


Processing Behavior


Feature Holding


Dependencies None
Aliases DEMGridGenerator
History This transformer was previously named DEMGridGenerator.

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