|Date:||28th January 2016|
This document explains the new/changed features of Iris in version 1.9 (View all changes.)
Support for running on Python 3.4 has been added to the whole code base. Some features which depend on external libraries will not be available until they also support Python 3, namely:
- gribapi does not yet provide a Python 3 interface
Added the UM pseudo level type to the information made available in the STASH_TRANS table in iris.fileformats.um._ff_cross_references
When reading “cell_methods” attributes from NetCDF files, allow optional whitespace before the colon. This is not strictly in the CF spec, but is a common occurrence.
Basic cube arithemetic (plus, minus, times, divide) now supports lazy evaluation.
iris.analysis.cartography.rotate_winds() can now operate much faster on multi-layer (i.e. > 2-dimensional) cubes, as it calculates rotation coefficients only once and reuses them for additional layers.
Linear regridding of a multi-layer (i.e. > 2-dimensional) cube is now much faster, as it calculates transform coefficients just once and reuses them for additional layers.
Ensemble statistics can now be saved to GRIB2, using Product Definition Template 4.11.
Loading of NetCDF data with ocean vertical coordinates now returns a ‘depth’ in addition to an ‘eta’ cube. This operates on specific defined dimensionless coordinates : see CF spec version 1.6, Appendix D.
Added a new point-in-cell regridding scheme, iris.experimental.regrid.PointInCell.
Added iris.analysis.WPERCENTILE() - a new weighted aggregator for calculating percentiles.
Added cell-method translations for LBPROC=64 and 192 in UM files, encoding ‘zonal mean’ and ‘zonal+time mean’.
Support for loading GRIB2 messages defined on a Lambert conformal grid has been added to the GRIB2 loader.
Data on potential-temperature (theta) levels can now be saved to GRIB2, with a fixed surface type of 107.
Added several new helper functions for file-save customisation, (see also : Saving Iris Cubes):
Loading data from GRIB2 now supports most of the currently defined ‘data representation templates’ : code numbers 0, 1, 2, 3, 4, 40, 41, 50, 51 and 61.
When a Fieldsfile is opened for update as a iris.experimental.um.FieldsFileVariant, unmodified packed data in the file can now be retained in the original form. Previously it could only be stored in an unpacked form.
When reading and writing NetCDF data, the CF ‘flag’ attributes, “flag_masks”, “flag_meanings” and “flag_values” are now preserved through Iris load and save.
mo_pack was added as an optional dependency. It is used to encode and decode data in WGDOS packed form.