FME Feature Store (FFS) Writer Parameters

This specification is used to encrypt the output dataset for additional security. This exact passphrase must be used to decrypt this dataset when it is read again.

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

If checked, creates and outputs a spatial index for each feature store. The spatial 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 by the FFS reader.

Note: If a spatial index is created, Compression Level is ignored; to allow for efficient random access, a non-compressed .ffs file is output.

Reduces the size of the output dataset. A lower compression level will result in faster operation for both reading and writing, while a higher compression level will result in smaller file sizes.

Note: Compression is best suited for sequential access; to allow for efficient random access for spatial operations, it is disabled if Create Spatial Index set to Yes.

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.

Note: Strictly adhering to a schema can, in some cases, greatly reduce file size by removing unnecessary attributes. Additionally, enforcing both names and types may dramatically improve read performance of the output file.

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

Note: Storing the scanned schema is in addition to the attributes provided on the writer feature type. When schemas are requested of the output FFS, the writer feature type schema is preferred and returned. However, the scanned schema is accessible through FME ObjectsDevelopers use FME Objects primarily for manipulating attributes, geometry, and coordinate systems on features from within a Python script in FME Workbench; and running a workspace using WorkspaceRunner. You can install FME Objects from the Windows install panel., and is useful for improving visualization performance of the FFS file in the FME Data Inspector.

Specifies whether to try 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.

Note: Choosing to not determine attribute types may dramatically improve writing performance. This option is can be set to No if directing data to the FME Data Inspector.

• 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.

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.

Note: It may create issues in the workspace if you choose file sizes that are too small for a single feature, or files that are too large for your operating system to support (for example, 4-GB files on Windows 32-bit is not recommended).

When FFS files are passed between two machines with the same system encoding, no work is done. When FFS files are passed between two machines with different system encodings (for example, utf-8 and shift-jis), system-encoded strings from the first machine will need to be tagged or transcoded.

FFS files contain information about the system encoding of the machine on which they are created. When reading FFS files, FME uses this information to tag and transcode on-the-fly. Taggable strings, such as attribute values, that have been left as system-encoded, are retagged with an explicit encoding name. System-encoded strings that can't be tagged, such as attribute names, are instead transcoded.

The Target String Transcoding parameter is used to preemptively perform the tagging and transcoding of new FFS files while writing, instead of while reading. (Note that the same transcoding/tagging will happen whether or not this setting is used – the difference is when the processing is done.)

By default, this parameter is blank, which means that no tagging or string transcoding is performed while writing. The reader will still be required to do all of the work.

When you select an encoding from the list (for example, shift-jis or utf-16), then FME will transcode any untaggable system-encoded strings to the selected destination encoding, and tag the rest of the system-encoded strings with the writer's system encoding. If the FFS file is later read on a machine with the system encoding that matches the one you selected, no tagging or encoding work will need to be performed during the read.