Zarr Writer Feature Type Parameters

To access feature type parameters, click the gear icon on a feature type in the workspace. This opens the Feature Type Parameter Editor.

Tip  To always display the editor in FME Workbench, you can select View > Windows > Parameter Editor.

General

All feature types share similar General parameters, which may include Feature Type Name, Reader or Writer information, and Geometry.

In most Writer Feature Type parameter dialogs, you can also control Dynamic Schema Definitions. Some database formats accept Table or Index Qualifier prefixes on the output table feature type.

Raster: Compression

Compression Method

This option sets the compression method: 

  • None
  • BLOSC
  • LZ4
  • LZMA
  • ZLIB
  • ZSTD
  • GZIP

Different algorithms will compress and decompress faster and smaller, depending on the type of data and environment. All of these algorithms will compress the data losslessly, so a compressed Zarr dataset will be identical to the original Zarr dataset.

BLOSC is the default compressor for the Zarr -Python library. It tends to be the fastest while only compromising a bit of compression ratio. It is also the most configurable compressor. For a more widely supported compressor, consider using LZ4 or LZMA.

Additional options can be set for compression levels.

Blosc

Blosc is a meta-compressor, which means that it can use a range of compression libraries. This option sets the compressor for Blosc to use.

  • blosclz (default)
  • lz4
  • lz4hc
  • zlib
  • zstd

This option sets the desired compression level of the output dataset.

Value

Number between 1 and 9:

  • 0 – minimum amount of compression
  • 9 – slowest option; provides the maximum amount of compression

Default

5

This option sets the shuffle for Blosc to use:

  • Byte – This is the default shuffle and should be used in most cases.
  • Bit – For numeric arrays, Bit shuffle will likely yield a higher compression ratio but this option will be slower.
  • None – There are very few use cases where None should be used.

LZ4 Acceleration Factor

This option sets the desired compression level of the output dataset.

Value

Number greater than 0:

  • 1 – fastest, least-compressed value possible.
  • 2 – slowest but most-compressed option, with each step gaining about +3% speed

Maximum Value

65537

Default

1

LZMA Compression Preset

This option sets the desired compression level of the output dataset.

Value

Number between 0 and 9:

  • 0 – minimum amount of compression
  • 9 – slowest option; provides the maximum amount of compression

Default

6

ZLIB Compression Level

Value

Number between 0 and 9:

  • 1 – minimum amount of compression
  • 9 – slowest option; provides the maximum amount of compression

Default

6

ZSTD Compression Level

Value

Number between 0 and 9:

  • 0 – minimum amount of compression
  • 22 – slowest option; provides the maximum amount of compression

Default

13

GZIP Compression Level

Value

Number between 1 and 9:

  • 0 – minimum amount of compression
  • 9 – slowest option; provides the maximum amount of compression

Default

6

Advanced

This option sets the logical path of the raster.

Default

If present: zarr_logical_path

If not present: fme_basename

Expected Format

UNIX path starting with a forward slash (/).

For example,

/foo/bar would create an array in ZARR.zarr/foo/bar

This option is used to set the slice index of the array.

Default

If present: zarr_slice_index

Expected Format

[\d(,\d)*]

For example, if a raster is 4 dimensions (n, t, y, x), the two-dimensional array slice with n=2, t=1 would have a slice index of [2,1].