# cfdm.CellMeasure¶

class cfdm.CellMeasure(measure=None, properties=None, data=None, source=None, copy=True, _use_data=True)[source]

Bases: cfdm.mixin.netcdf.NetCDFVariable, cfdm.mixin.netcdf.NetCDFExternal, cfdm.mixin.propertiesdata.PropertiesData, cfdm.mixin.files.Files, cfdm.core.cellmeasure.CellMeasure

A cell measure construct of the CF data model.

A cell measure construct provides information that is needed about the size or shape of the cells and that depends on a subset of the domain axis constructs. Cell measure constructs have to be used when the size or shape of the cells cannot be deduced from the dimension or auxiliary coordinate constructs without special knowledge that a generic application cannot be expected to have.

The cell measure construct consists of a numeric array of the metric data which spans a subset of the domain axis constructs, and properties to describe the data. The cell measure construct specifies a “measure” to indicate which metric of the space it supplies, e.g. cell horizontal areas, and must have a units property consistent with the measure, e.g. square metres. It is assumed that the metric does not depend on axes of the domain which are not spanned by the array, along which the values are implicitly propagated. CF-netCDF cell measure variables correspond to cell measure constructs.

NetCDF interface

The netCDF variable name may be accessed with the nc_set_variable, nc_get_variable, nc_del_variable, and nc_has_variable methods.

The netCDF variable group structure may be accessed with the nc_set_variable, nc_get_variable, nc_variable_groups, nc_clear_variable_groups, and nc_set_variable_groups methods.

The selection of properties to be written as netCDF global attributes may be accessed with the nc_global_attributes, nc_clear_global_attributes, and nc_set_global_attribute methods.

New in version (cfdm): 1.7.0

Initialisation

Parameters
measure: str, optional

Set the measure that indicates the metric given by the data array.

The measure may also be set after initialisation with the set_measure method.

Parameter example:

measure='area'

properties: dict, optional

Set descriptive properties. The dictionary keys are property names, with corresponding values.

Properties may also be set after initialisation with the set_properties and set_property methods.

Parameter example:

properties={'standard_name': 'cell_area'}

data: data_like, optional

Set the data.

A data_like object is any object that can be converted to a Data object, i.e. numpy array_like objects, Data objects, and cfdm instances that contain Data objects.

The data also may be set after initialisation with the set_data method.

source: optional

Convert source, which can be any type of object, to a CellMeasure instance.

All other parameters, apart from copy, are ignored and their values are instead inferred from source by assuming that it has the CellMeasure API. Any parameters that can not be retrieved from source in this way are assumed to have their default value.

Note that if x is also a CellMeasure instance then cfdm.CellMeasure(source=x) is equivalent to x.copy().

copy: bool, optional

If True (the default) then deep copy the input parameters prior to initialisation. By default the parameters are not deep copied.

## Inspection¶

Methods

 dump A full description of the cell measure construct. identity Return the canonical identity. identities Return all possible identities.

Attributes

 construct_type Return a description of the construct type.

## Properties¶

Methods

 del_measure Remove the measure. get_measure Return the measure. has_measure Whether the measure has been set. set_measure Set the measure. del_property Remove a property. get_property Return a property. has_property Whether a property has been set. set_property Set a property. properties Return all properties. clear_properties Remove all properties. del_properties Remove properties. set_properties Set properties.

## Data¶

Methods

 apply_masking Apply masking as defined by the CF conventions. del_data Remove the data. get_data Return the data. has_data Whether or not the construct has data. set_data Set the data. insert_dimension Expand the shape of the data array. squeeze Remove size one axes from the data array. transpose Permute the axes of the data array.

Attributes

 array A numpy array deep copy of the data. data Return the data. datetime_array An independent numpy array of date-time objects. dtype Data-type of the data elements. ndim The number of dimensions in the data array. shape A tuple of the data array’s dimension sizes. size The number of elements in the data array.

## Miscellaneous¶

Methods

 copy Return a deep copy. creation_commands Returns the commands to create the cell measure construct. equals Whether two cell measure constructs are the same. has_bounds Whether or not there are cell bounds. uncompress Uncompress the construct. get_filenames Return the name of the file or files containing the data. get_original_filenames The names of files containing the original data and metadata. to_memory Bring data on disk into memory.

## NetCDF¶

Methods

 nc_del_variable Remove the netCDF variable name. nc_get_variable Return the netCDF variable name. nc_has_variable Whether the netCDF variable name has been set. nc_set_variable Set the netCDF variable name. nc_get_external Whether a construct matches an external netCDF variable. nc_set_external Set external status of a netCDF variable.

### Groups¶

Methods

 nc_variable_groups Return the netCDF variable group hierarchy. nc_clear_variable_groups Remove the netCDF variable group hierarchy. nc_set_variable_groups Set the netCDF variable group hierarchy.

## Special¶

Methods

 __deepcopy__ Called by the copy.deepcopy function. __getitem__ Return a subspace defined by indices. __repr__ Called by the repr built-in function. __str__ Called by the str built-in function.

## Docstring substitutions¶

Methods

 _docstring_special_substitutions Return the special docstring substitutions. _docstring_substitutions Returns the substitutions that apply to methods of the class. _docstring_package_depth Returns the class {{package}} substitutions package depth. _docstring_method_exclusions Returns method names excluded in the class substitutions.