3.18.2

2025-10-16

• Python 3.9 support removed (#896)
• Allow regridding for very large grids. New keyword parameter tocf.Field.regrids and cf.Field.regridc: dst_grid_partitions (#878)
• Changed dependency: Python>=3.10.0

What's Changed

• cf.Data.arctan2(): Fixes #890 by trying to conform valid units first. by @ThatDesert in #891
• Remove support for Python 3.9 (EOL) by @davidhassell in #897
• Unit test skips based on lack of optional module availability by @sadielbartholomew in #898
• Allow regridding for very large grids by @davidhassell in #893

Full Changelog: v3.18.1...v3.18.2

3.18.1

2025-08-20

• New methods to allow changing units in a chain: cf.Field.to_units, cf.Data.to_units (#874)
• Allow multiple conditions for the same axis in cf.Field.subspace and cf.Field.indices (#881)
• Fix bug in cf.Field.collapse that causes a ValueError to be raised for missing external cell measures data (#885)
• New dependency: distributed>=2025.5.1
• Changed dependency: cfdm>=1.12.3.0, <1.12.4.0

What's Changed

• Docs: fix DOI badge at source & patch in built docs (to avoid rebuild) by @sadielbartholomew in #877
• New to_units methods to allow changing units in a chain by @davidhassell in #875
• Add distributed as required dependency with version pin by @sadielbartholomew in #880
• cf.Field.subspace - allow multiple subspacing conditions for the same axis by @davidhassell in #882
• cf.Field.collapse fails when cell measure has external data by @davidhassell in #886
• Added troubleshooting for installing cf next to Jupyter and conda by @ThatDesert in #884

New Contributors

• @ThatDesert made their first contribution in #884

Full Changelog: v3.18.0...v3.18.1

3.18.0

2025-06-05

• Implement lossy compression via quantization (#870)
• New quantization class: cf.Quantization (#870)
• New quantization methods: cf.Field.get_quantization, cf.Field.get_quantize_on_write, cf.Field.set_quantize_on_write, cf.Field.del_quantize_on_write (#870)
• New keyword parameter to cf.write: chunk_cache (#871)
• Read Zarr datasets with cf.read (#863)
• Update CF aggregation keywords (#868)
• New keyword parameter to cf.DimensionCoordinate.create_bounds: inplace (#855)
• Set new minimum version of dask: 2025.5.1 (#866)
• Changed dependency: cfdm>=1.12.2.0, <1.12.3.0
• Changed dependency: dask>=2025.5.1

3.17.0

2025-04-02

• Set new minimum version of dask: 2025.2.0 (#849)
• Set a new minimum version of numpy: 2.0.0 (#843)
• Replace dataset aggregation functionality (CFA) with that imported from cfdm (#841)
• New keyword parameter to cf.Field.compute_vertical_coordinates: key (#802)
• New keyword parameter to cf.histogram: density (#794)
• Fix bug that caused Data._axes to be incorrect after a call to cf.Field.collapse (#857)
• Fix bug that caused wrong directions from cf.DimensionCoordinate.direction (#859)
• Changed dependency: Python>=3.9.0
• Changed dependency: numpy>=2.0.0
• Changed dependency: cfdm>=1.12.1.0, <1.12.2.0
• Changed dependency: dask>=2025.2.0, <=2025.3.0
• Changed dependency: netCDF4>=1.7.2
• Changed dependency: cftime>=1.6.4
• Changed optional dependency: esmpy>=8.7.0
• Removed dependency (now incorporated into cfdm): h5py
• Removed dependency (now incorporated into cfdm): h5netcdf
• Removed dependency (now incorporated into cfdm): s3fs

3.16.3

2025-01-28

• Allow 'nearest_dtos' 2-d regridding to work with discrete sampling geometry source grids (#832)
• New method: cf.Field.filled (#811)
• New method: cf.Field.is_discrete_axis (#784)
• Include the UM version as a field property when reading UM files (#777)
• Fix bug that caused climatological time collapses within/over days to fail (#809)
• New keyword parameter to cf.Field.derivative: ignore_coordinate_units (#807)
• Allow access to netCDF-4 files in S3 object stores (#712)
• New class cf.H5netcdfArray
• New class cf.NetCDF4Array
• New class cf.CFAH5netcdfArray
• New class cf.CFANetCDF4Array
• Replace core dask functionality with that imported from cfdm (#839)
• Fix bug that sometimes puts an incorrect radian-1 or radian-2 in the returned units of the differential operator methods and functions (#807)
• Fix bug where cf.example_fields returned a list of Fields rather than a Fieldlist (#725)
• Fix bug where combining UGRID fields erroneously creates an extra axis and broadcasts over it (#784)
• Fix bug where cf.normalize_slice doesn't correctly handle certain cyclic slices (#774)
• Fix bug where cf.Field.subspace doesn't always correctly handle global or near-global cyclic subspaces (#828)
• New dependency: h5netcdf>=1.3.0
• New dependency: h5py>=3.10.0
• New dependency: s3fs>=2024.6.0
• Changed dependency: numpy>=1.15,<2.0
• Changed dependency: 1.11.2.0<=cfdm<1.11.3.0
• Changed dependency: cfunits>=3.3.7
• Changed dependency: dask>=2024.6.0,<=2024.7.1

3.16.2

2024-04-26

• Improve the performance of reading and accessing the data of PP and UM fields files (#746)
• Improve cf.Field.collapse performance by lazily computing reduced axis coordinates (#741)
• Improve cf.Field.__getitem__ performance by not re-calculating axis cyclicity (#744)
• Reduce output CFA netCDF file size by setting the HDF5 chunksizes of CFA variables to be no larger than required (#739)
• Allow a halo to be added by cf.Field.indices and cf.Field.subspace (#759)
• Added spherical regridding to discrete sampling geometry destination grids (#716)
• Added 3-d spherical regridding to cf.Field.regrids, and the option to regrid the vertical axis in logarithmic coordinates to cf.Field.regrids and cf.Field.regridc (#715)
• New keyword parameter to cf.Field.regrids and cf.Field.regridc: return_esmpy_regrid_operator (#766)
• New keyword parameters to cf.wi: open_lower and open_upper (#740)
• Fix misleading error message when it is not possible to create area weights requested from cf.Field.collapse (#731)
• Fix bug in cf.read when reading UM files that caused LBPROC value 131072 (Mean over an ensemble of parallel runs) to be ignored (#737)
• Fix bug in cf.aggregate that sometimes put a null transpose operation into the Dask graph when one was not needed (#754)
• Fix bug in cf.aggregate that caused a failure when property values were numpy arrays with two or more elements (#764)
• Fix bug in cf.aggregate that didn't correctly handle the "actual_range" CF attribute (#764)
• Fix bug whereby Field.cyclic is not updated after a Field.del_construct operation (#758)
• Fix bug that meant cyclic() always returned an empty set for domains produced by cf.Field.domain (#762)
• Changed dependency: cfunits>=3.3.7
• Changed dependency: netCDF4>=1.6.5

3.16.1

2024-03-01

• Allow DSG trajectories with identical trajectory_id values to be aggregated (#723)
• New methods: cf.Field.pad_missing and cf.Data.pad_missing (#717)
• Fix occasional bug when calculating UGRID cell areas when non-spatial coordinates span the discrete axis (#721)
• New keyword parameter to cf.Field.insert_dimension: constructs (#719)
• Added the cell_measures and coordinates keyword arguments to cf.Field.weights (#709)
• Added the cell_measures, coordinates, return_cell_measure, and methods keyword arguments to cf.Field.cell_area (#709)
• Allow cf.Data to be initialised with xarray.DataAarray (#706)
• Fix bug that caused cf.Field.del_file_location to fail when updating its metadata constructs (#707)
• Fix bug that caused incorrect data arrays in some cyclic subspaces created by cf.Field.subspace and cf.Field.__getitem__ (#713)
• Changed dependency: 1.11.1.0<=cfdm<1.11.2.0

3.16.0

2023-12-06

• Implemented the reading and manipulation of UGRID mesh topologies (#696)
• New methods: cf.Field.cell_connectivity, cf.Field.cell_connectivities (#696)
• New methods: cf.Field.domain_topology, cf.Field.domain_topologies (#696)
• New method: cf.Data.masked_values (#696)
• New method: cf.Data.arctan2 (#38)
• Fix bug that caused cf.Field.collapse to give incorrect results for the "sum", "sum_of_weights" and "sum_of_weights2" methods, only in the case that weights have been requested (#701)
• Changed dependency: 1.11.0.0<=cfdm<1.11.1.0
• New dependency: scipy>=1.10.0

3.15.4

2023-10-10

• Record dimension coordinate cell characteristics (#692)
• New set of methods to query, set, del, and get_cell_characteristics
• Fix bug in cf.Field.match_by_construct that always returned True for 1-d constructs whose axis is not in the data, even when the
  criterion was not matched (#691)
• Fix bug that prevented "https://" netCDF files from being read (#699)

3.15.3

2023-08-31

• Prevent unlimited dimensions from being written to CFA-netCDF files (#689)