ER Mapper ECW Reader Parameters

Dataset Parameters

This parameter allows you to choose different naming schemes, and the number of feature types generated for the reader.

Feature type name choices:

  • From File Name(s): Generates one feature type per source filename.
  • From Format Name: Produces only a single feature type containing the format name.

By default, the GCP information is preserved as properties on the raster geometry.

If you select this checkbox, the GCP information, including a GCP projection, will be read from the file and applied to the raster data as an affine transformation.

GCP Interpolation Method

Specifies the interpolation method used to apply a GCP projection to the raster data.

  • Nearest Neighbor: Applies a projection based on the value of the pixel closest to the GCP. This method is the least resource-intensive, but also produces the lowest resolution GCP.
  • Bilinear: Applies a projection by averaging the closest 2x2 neighborhood of pixel values surrounding the GCP. This method produces higher-quality results than Nearest Neighbor.
  • Bicubic: Applies a projection by applying a weighted average of the closest 4x4 neighborhood of pixel values surrounding the GCP, with closer pixels weighted higher than farther pixels. Bicubic interpolation requires the most amount of processing time.

Additional Attributes to Expose

Use this parameter to expose Format Attributes in Workbench when you create a workspace:

  • In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
  • In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.

Use Search Envelope

Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that intersect with the bounding box are returned.

If all four coordinates of the search envelope are specified as 0, the search envelope will be disabled.

When selected, this parameter removes any portions of imported features being read that are outside the Search Envelope.

The example below illustrates the results of the Search Envelope when Clip to Search Envelope is not selected (set to No) and when it is selected (set to Yes).

  • No: Any features that cross the search envelope boundary will be read, including the portion that lies outside of the boundary.
  • Yes: Any features that cross the search envelope boundary will be clipped at the boundary, and only the portion that lies inside the boundary will be read. The underlying function for the Clip to Search Envelope function is an intersection; however, when Clip to Search Envelope is selected, a clipping operation is also performed in addition to the intersection.

Pyramid Level to Read

This parameter specifies the pyramid level from which to read.

Pyramid level 0 represents the original raster data. Values greater than 0 represent increasingly reduced levels of image resolution.

Each pyramid level has half the number of rows and columns of the previous level.

Cache Size Calculation

This parameter specifies how FME should calculate the ECW compression cache size.

  • Auto (default) – FME will calculate a cache size that is appropriate for the size of the raster data. This option should be preferred.
  • Manual – FME will use the value of the Compression Cache Size (MB) parameter. This option should be used if a cache error occurs. The error will contain information about the prescribed manual cache size.

Compression Cache Size (MB)

This parameter specifies the size of the ECW compression cache in megabytes (MB).

This parameter is only enabled when the Cache Size Calculation parameter is set to Manual.