CF boundary variable

This class represents the boundaries of an axis or an auxiliary longitude-latitude grid.

The class manages the boundary information for an axis (2 vertices per element) or an auxiliary longitude-latitude grid (4 vertices per element).

Super classes

ncdfCF::CFObject -> ncdfCF::CFData -> CFBounds

Active bindings

friendlyClassName

(read-only) A nice description of the class.

length

(read-only) The length of the second dimension of the data, i.e. the number of boundary values.

vertices

(read-only) The length of the first dimension of the data, i.e. the number of vertices that make up a boundary.

values

Set or retrieve the boundary values of this object. Upon retrieval, values are read from the netCDF resource, if there is one, upon first access and cached thereafter. Upon setting values, if there is a linked netCDF resource, this object will be detached from it.

Methods

Public methods

• CFBounds$new()

• CFBounds$print()

• CFBounds$range()

• CFBounds$copy()

• CFBounds$subset()

• CFBounds$append()

• CFBounds$write()

Inherited methods

• ncdfCF::CFObject$append_attribute()
• ncdfCF::CFObject$attach_to_group()
• ncdfCF::CFObject$attribute()
• ncdfCF::CFObject$attributes_identical()
• ncdfCF::CFObject$delete_attribute()
• ncdfCF::CFObject$print_attributes()
• ncdfCF::CFObject$set_attribute()
• ncdfCF::CFObject$write_attributes()
• ncdfCF::CFData$detach()
• ncdfCF::CFData$dim()

---

Method new()

Create an instance of this class.

Usage

CFBounds$new(
  var,
  group,
  values,
  start = NA,
  count = NA,
  attributes = data.frame(),
  owner_dims = 1L
)

Arguments

var

The name of the boundary variable when creating a new boundary variable. When reading a boundary variable from file, the NCVariable object that describes this instance.

group

The CFGroup that this instance will live in.

values

Optional. The values of the boundary variable. This must be a numeric matrix whose first dimension has a length equal to the number of vertices for each boundary, and the second dimension is as long as the CFObject instances that use these boundary values. Ignored when argument var is a NCVariable object.

start

Optional. Vector of indices where to start reading boundary data along the dimensions of the data. The vector must be NA to read all data, otherwise it must have a length equal to the dimensionality of the owning object + 1.

count

Optional. Vector of number of elements to read along each dimension of the boundary data. The vector must be NA to read to the end of each dimension, otherwise it must have a length equal to the dimensionality of the owning object + 1.

attributes

Optional. A data.frame with the attributes of the boundary object. When an empty data.frame (default) and argument var is an NCVariable instance, attributes of the bounds object will be taken from the netCDF resource.

owner_dims

Optional, the number of dimensions of the object that these boundary values pertain to. Default is 1.

Returns

A new instance of this class.

---

Method print()

Print a summary of the object to the console.

Usage

CFBounds$print(attributes = TRUE, ...)

Arguments

attributes

Default TRUE, flag to indicate if the attributes of the boundary values should be printed.

...

Arguments passed on to other functions. Of particular interest is width = to indicate a maximum width of attribute columns.

---

Method range()

Retrieve the lowest and highest value in the bounds.

Usage

CFBounds$range()

---

Method copy()

Create a copy of this bounds object The copy is completely separate from self, meaning that both self and all of its components are made from new instances.

Usage

CFBounds$copy(name = "", group)

Arguments

name

The name for the new bounds object. If an empty string is passed, will use the name of this bounds object.

group

The CFGroup where the copy of this axis will live.

Returns

The newly created bounds object.

---

Method subset()

Return a boundary variable spanning a smaller coordinate range. This currently only applies to 1-D axes.

This method returns boundary values which span the range of indices given by the rng argument.

Usage

CFBounds$subset(group, rng)

Arguments

group

The CFGroup where the copy of these bounds will live.

rng

The range of values from this bounds object to include in the returned object.

Returns

A CFBounds instance covering the indicated range of indices.

---

Method append()

Append boundary values at the end of the current values of the boundary variable.

Usage

CFBounds$append(from, group)

Arguments

from

An instance of CFBounds whose values to append to the values of this boundary variable.

group

The CFGroup where the copy of these bounds will live.

Returns

A new CFBounds instance with values from this boundary variable and the from boundary variable appended. If argument from is NULL, return NULL.

---

Method write()

Write the boundary variable to a netCDF file. This method should not be called directly; instead, CFVariable$save() will call this method automatically.

Usage

CFBounds$write(object_name)

Arguments

object_name

The name of the object that uses these boundary values, usually an axis but could also be an auxiliary CV or a parametric Z axis.