sandplover.mask.ThresholdValueMask

class sandplover.mask.ThresholdValueMask(*args, threshold, cube_key=None, **kwargs)

Threshold value mask.

This mask implements a binarization of a raster based on a threshold values.

__init__(*args, threshold, cube_key=None, **kwargs)

Initialize the base mask attributes and methods.

This intialization tries to determine the types of intputs given to the initializer and proceeds from there.

Parameters:

• mask_type (str) – Descriptor of the mask type.

• *args

Methods

__init__(*args, threshold[, cube_key])	Initialize the base mask attributes and methods.
show([ax, title, ticks, colorbar])	Show the mask.
trim_mask(*args[, value, axis, length])	Replace a part of the mask with a new value.

Attributes

integer_mask	Binary mask values as integer
mask	Binary mask values.
mask_type	Type of the mask (string)
shape
threshold	Generic property for ThresholdValueMask threshold.
variables

__getitem__(var)

Implement slicing.

Return values directly from the mask. Supported variables are only ‘mask’ or ‘integer’.

property integer_mask

Binary mask values as integer

Important

integer_mask is a boolean array as 0 and 1 (integers). It is not suitible for multidimensional array indexing; see also mask.

Read-only mask attribute.

Type:

ndarray

property mask

Binary mask values.

Important

mask is a boolean array (not integer). See also integer_mask.

Read-only mask attribute.

Type:

ndarray

property mask_type

Type of the mask (string)

show(ax=None, title=None, ticks=False, colorbar=False, **kwargs)

Show the mask.

The Mask is shown in a matplotlib axis with imshow. The mask values are accessed from integer_mask, so the display will show as 0 for False and 1 for True. Default colormap is black and white.

Hint

Passes **kwargs to matplotlib.imshow.

Parameters:

ax (matplotlib.pyplot.Axes) – Which axes object to plot into.

property threshold

Generic property for ThresholdValueMask threshold.

trim_mask(*args, value=False, axis=1, length=None)

Replace a part of the mask with a new value.

This is sometimes necessary before using a mask in certain computations. Most often, this method is used to manually correct domain edge effects.

Parameters:

• *args (BaseCube subclass, optional) – Optionally pass a Cube object to the mask, and the dimensions to trim/replace the mask by will be inferred from the cube. In this case, axis and length have no effect.

• value – Value to replace in the trim region with. Default is False.

• axis – Which edge to apply the trim of length to. Default is 1, the top domain edge.

• length – The length of the trim. Note that this is not the array index.

Examples