This class holds the data that is extracted from a CFVariable
using the data(), subset() or profile() method. The instance of this
class will additionally have the axes and other relevant information such
as its attributes (as well as those of the axes) and the coordinate
reference system.
Otherwise, a CFArray is detached from the data set where it was derived
from. It is self-contained in the sense that all its constituent parts
(axes, bounds, attributes, etc) are available and directly linked to the
instance. For performance reasons, axes and their parts (e.g. bounds) are
shared between instances of CFArray and CFVariable.
The class has a number of utility functions to extract the data in specific formats:
raw(): The data without any further processing. The axes are
as they are stored in the netCDF resource; there is thus no guarantee as to
how the data is organized in the array. Dimnames will be set.
array(): An array of the data which is organized as a standard R array
with the axes of the data permuted to Y-X-others and Y-values in decreasing
order. Dimnames will be set.
terra(): The data is returned as a terra::SpatRaster (3D) or
terra::SpatRasterDataset (4D) object, with all relevant structural
metadata set. Package terra must be installed for this to work.
data.table(): The data is returned as a data.table, with all data
points on individual rows. Metadata is not maintained. Package data.table
must be installed for this to work.
The temporal axis of the data, if present, may be summarised using the
summarise() method. The data is returned as a new CFArray instance.
In general, the metadata from the netCDF resource will be lost when exporting to a different format insofar as those metadata are not recognized by the different format.
ncdfCF::CFObject -> ncdfCF::CFVariableBase -> CFArray
dimnames(read-only) Retrieve dimnames of the data object.
Inherited methods
ncdfCF::CFObject$add_coordinates()ncdfCF::CFObject$append_attribute()ncdfCF::CFObject$attribute()ncdfCF::CFObject$delete_attribute()ncdfCF::CFObject$print_attributes()ncdfCF::CFObject$set_attribute()ncdfCF::CFObject$write_attributes()ncdfCF::CFVariableBase$profile()ncdfCF::CFVariableBase$summarise()ncdfCF::CFVariableBase$time()
new()Create an instance of this class.
CFArray$new(name, group, values, values_type, axes, crs, attributes)nameThe name of the object.
groupThe group that this data should live in. This is usually an in-memory group, but it could be a regular group if the data is prepared for writing into a new netCDF file.
valuesThe data of this object. The structure of the data depends on the method that produced it.
values_typeThe unpacked netCDF data type for this object.
axesA list of CFAxis descendant instances that describe the
axes of the argument values.
crsThe CFGridMapping instance of this data object, or NULL
when no grid mapping is available.
attributesA data.frame with the attributes associated with the
data in argument values.
An instance of this class.
...Arguments passed on to other functions. Of particular interest
is width = to indicate a maximum width of attribute columns.
raw()Retrieve the data in the object exactly as it was produced
by the operation on CFVariable.
CFArray$raw()The data in the object. This is usually an array with the
contents along axes varying.
array()Retrieve the data in the object in the form of an R array, with axis ordering Y-X-others and Y values going from the top down.
CFArray$array()An array of data in R ordering.
append()Append the data from another CFArray instance to the
current instance, along one of the axes. The operation will only
succeed if the axes other than the one to append along have the same
coordinates and the coordinates of the axis to append along have to be
monotonically increasing or decreasing after appending.
CFArray$append(from, along)fromThe CFArray instance to append from.
alongThe name of the axis to append along. This must be a single
character string and the named axis has to be present both in self
and in the CFArray instance in argument from.
self, invisibly, with the arrays from self and from
appended.
terra()Convert the data to a terra::SpatRaster (3D) or a
terra::SpatRasterDataset (4D) object. The data
will be oriented to North-up. The 3rd dimension in the data will become
layers in the resulting SpatRaster, any 4th dimension the data sets.
The terra package needs to be installed for this method to work.
CFArray$terra()A terra::SpatRaster or terra::SpatRasterDataset instance.
data.table()Retrieve the data in the object in the form of a
data.table. The data.table package needs to be installed for this
method to work.
CFArray$data.table(var_as_column = FALSE)var_as_columnLogical to flag if the name of the variable should
become a column (TRUE) or be used as the name of the column with the
data values (FALSE, default). Including the name of the variable as a
column is useful when multiple data.tables are merged into one.
A data.table with all data points in individual rows. All axes
will become columns. Two attributes are added: name indicates the
long name of this data variable, units indicates the physical unit of
the data values.
fnThe name of the netCDF file to create.
packLogical to indicate if the data should be packed. Packing is only useful for numeric data; packing is not performed on integer values. Packing is always to the "NC_SHORT" data type, i.e. 16-bits per value.
Self, invisibly.
clone()The objects of this class are cloneable with this method.
CFArray$clone(deep = FALSE)deepWhether to make a deep clone.