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.

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Typical Uses

  • Imprinting vector data onto an existing raster background (such as orthophotos)
  • Updating a raster image from vector data

How does it work?

The VectorOnRasterOverlayer receives vector geometries (points, lines, areas) and/or point clouds, and rasterizes them onto an input raster feature, producing a single output raster.

For vector input features, the fme_color attribute determines the pixel color in the raster. Pixel values for red, green, and blue bands will be taken from the corresponding component of a feature's fme_color attribute. Pixel values for gray bands will be the average of the fme_color components.

Polygonal features may also optionally have an fme_fill_color attribute; in this case, the outer boundary will be drawn using fme_color and the inner area will be drawn using fme_fill_color.

For point clouds, pixel coloring may be done using either the color or intensity component.

The Z coordinates of the input vector features are used to generate pixel values for numeric bands.

Line weights are not supported, and features will be drawn at a width of one (1) pixel. Lines and points may be buffered prior to entering the transformer to increase their visibility.

Alpha value and anti-aliasing options are available. The resolution, extents, and interpretation of the output raster will be identical to the input raster.

Vector data extents do not need to match the extents of the raster - if they extend beyond the raster, they will be clipped.

Attributes from the input vector or point cloud features may be merged onto the output raster, with a list attribute option available.

Features with no color attribute (or point clouds without an intensity component, if selected) will be discarded and output via the <Rejected> port, as will extra or invalid raster images.

Aggregate rasters are not supported, but they may be deaggregated and mosaicked prior to entering the transformer. Aggregate vector data may be rasterized, but may produce duplicate records if a list attribute is created.

This transformer supports raster band selection. The RasterSelector can be used to modify selection.

Usage Notes

  • To rasterize vectors/point clouds and create a new raster (not drawing on an existing one), use the ImageRasterizer.
  • To add labels, you can use a Labeller and TextStroker prior to the VectorOnRasterOverlayer.
  • For fine control over cartographic styling, consider using the MapnikRasterizer.
  • If your background raster spans more than one image, use a RasterMosaicker prior to the VectorOnRasterOverlayer.
  • To produce elevation rasters, use the NumericRasterizer.
  • To increase size and visibility on vector features, consider using the Bufferer.
  • To colorize a point cloud from a raster, use the PointCloudOnRasterComponentSetter.

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

Group-Based

Feature Holding

Yes

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

Rasters

Spatial Analysis

FME Community

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