cf.Transform

class cf.Transform(*args, **kwargs)

Bases: cf.utils.CfDict

A CF transform construct.

The named parameters and their values of the transformation (i.e. the transformation’s mappings) comprise the object’s key-value pairs.

A transformation is equivalent to either a CF-netCDF ‘formula_terms’ or ‘grid_mapping’ property. DCH DCH DCH

In the ‘formula_terms’ case, a mapping to a coordinate (as opposed to another field) uses the coordinate’s domain key name as a pointer rather than a copy of the coordinate itself.

Examples

>>> t
<CF Transform: atmosphere_sigma_coordinate>
>>> print t.dump()
atmosphere_sigma_coordinate transform
-------------------------------------
Transform['ps'] = <CF Field: surface_air_pressure(73, 96)>
Transform['ptop'] = 0.05
Transform['sigma'] = 'dim0'

>>> t
<CF Transform: rotated_latitude_longitude>
>>> print t.dump()
rotated_latitude_longitude transform
------------------------------------
Transform['grid_north_pole_latitude'] = 33.67
Transform['grid_north_pole_longitude'] = 190.0

Initialization

Parameters :

args, kwargs :

Keys and values are initialized exactly as for a built-in dict. Keys are transform parameter names (such as ‘grid_north_pole_latitude’ or ‘sigma’) with appropriate values. Some key/value pairs are treated as special cases:

• If the key ‘standard_name’ is specified then it is assumed to be the standard name of a dimensionless vertical coordinate, and the transform represents a CF-netCDF formula_terms attribute. A ‘standard_name’ key is not created, but its value is assigned to the name attribute.
• If the key ‘grid_mapping_name’ is specified then is assumed that the transform represents a CF-netCDF grid mapping of the same name. A ‘grid_mapping_name’ key is created and its value is also assigned to the name attribute.

Examples

>>> t = Transform(grid_north_pole_latitude=38.0, 
...               grid_north_pole_longitude=190.0,
...               grid_mapping_name='rotated_latitude_longitude')

>>> t = Transform(p0=cf.Data(1000, 'hPa'), lev='dim1', 
...               standard_name='atmosphere_ln_pressure_coordinate')

Transform attributes

isformula_terms	True if the transform is a formula_terms.
isgrid_mapping	True if the transform is a grid_mapping.
name	The identifying name of the transformation.

Transform methods

clear
copy	Return a deep copy.
dump	Return a string containing a full description of the transform.
equals	True if two instances are equal, False otherwise.
get
get_keys	Return a list of the key names which match a regular expression.
has_key	Return true if and only if the dictionary contains the given key.
items
iteritems
iterkeys
itervalues
keys
pop
popitem
setdefault
update
values