FME Feature Store (FFS) Writer Parameters

Used to encrypt the output dataset for additional security.

If this parameter is not used when writing the output dataset, it is not necessary to specify it when reading it in again.

• LZ4 (fastest) (default) – Reduces the size of the dataset with an algorithm that is fast for both reading and writing. Results in larger file sizes than Zstandard compression.
• Zstandard – Reduces the size of the dataset with a general-purpose algorithm.
  • Compression Level (available only when Compression Method is set to Zstandard) is used to determine the tradeoff between writing speed and file size. Higher levels use more resources, but produce smaller files; lower levels compress more quickly, but create larger files.
• None – Does not reduce the size of the dataset.

Indicates whether features should be modified to adhere to the schema. This may include removing all unlisted user attributes before they are saved, or enforcing that attribute types match the type specified on the schema.

• No – (default) Features will be saved without modification.
• Yes – Attributes not specified on the schema will be stripped, and attributes specified on the schema will be saved with the specified type.

• Yes – Schemas will be recorded and stored in the output FFS file.
• No (default) – Schemas will not be passed to the output file.

Used to determine the types of attributes when scanning for schema (when Store Scanned Schema is set to Yes).

• Yes – FME will attempt to determine the correct type for each attribute (for example, int32, real64, etc.).
• No – All attributes will be treated as strings.

• Yes – Additional metadata will be recorded and stored in the output FFS file.
• No (default) – Metadata will not be stored in the output file. Metadata includes feature types, geometry types, feature count, and extents.

The scanned metadata is useful for improving visualization performance of the FFS file in the FME Data Inspector.

Coordinate systems may be extracted from input feature data sources, may come predefined with FME, or may be user-defined. FME allows different output and input coordinate systems, and performs the required coordinate conversions when necessary.

For systems that know their coordinate system, the Coordinate System field will display Read from Source and FME will read the coordinate system from the source dataset. For most other input sources, the field will display Unknown (which simply means that FME will use default values). In most cases, the default value is all you'll need to perform the translation.

You can always choose to override the defaults and choose a new coordinate system. Select More Coordinate Systems from the drop-down menu to open the Coordinate System Gallery.

Changing a Reprojection

To perform a reprojection, FME typically uses the CS-MAP reprojection engine, which includes definitions for thousands of coordinate systems, with a large variety of projections, datums, ellipsoids, and units. However, GIS applications have slightly different algorithms for reprojecting data between different coordinate systems. To ensure that the data FME writes matches exactly to your existing data, you can use the reprojection engine from a different application.

To change the reprojection engine, Select Workspace Parameters > Spatial > Reprojection Engine. In the example shown, you can select Esri (but the selection here depends on your installed applications):

If set to Yes, creates and outputs a spatial and feature index for each feature store. The index has the same base name as the FFS file, but will have an .fsi extension. Spatial Indexes are needed if the FFS file is later used as the source for spatial queries or feature types by the FFS reader.

Limits the size of each FFS file.

If a file exceeds the specified number of bytes, it will be closed and a new file will be created, with a numeric suffix starting at 1. A single spatial index is created for the group of files.