deltametrics.mask.CenterlineMask

class deltametrics.mask.CenterlineMask(*args, method='skeletonize', **kwargs)

Identify channel centerline mask.

A centerline mask object, provides the location of channel centerlines.

Examples

Initialize the CenterlineMask from elevation and flow data:

golfcube = dm.sample_data.golf()
cntmsk = dm.mask.CenterlineMask(
    golfcube['eta'][-1, :, :],
    golfcube['velocity'][-1, :, :],
    elevation_threshold=0,
    flow_threshold=0.3)

fig, ax = plt.subplots(1, 2, figsize=(8, 4))
golfcube.quick_show('eta', idx=-1, ax=ax[0])
cntmsk.show(ax=ax[1])
plt.show()

(png, hires.png)

__init__(*args, method='skeletonize', **kwargs)

Initialize the CenterlineMask.

Initialization of the centerline mask object requires a 2-D channel mask (can be the ChannelMask object or a binary 2-D array).

Parameters:

• channelmask (ChannelMask or ndarray) – The channel mask to derive the centerlines from

• is_mask (bool, optional) – Whether the data in arr is already a binary mask. Default value is False. This should be set to True, if you have already binarized the data yourself, using custom routines, and want to just store the data in the CenterlineMask object.

• method (str, optional) – The method to use for the centerline mask computation. The default method (‘skeletonize’) is a morphological skeletonization of the channel mask.

• kwargs (optional) – Keyword arguments for the ‘rivamap’ functionality.

Methods

__init__(*args[, method])	Initialize the CenterlineMask.
from_Planform(*args, **kwargs)
from_Planform_and_FlowMask(_Planform, ...)	Create from a Planform and a FlowMask.
from_array(_arr)	Create a CenterlineMask from an array.
from_mask(*args, **kwargs)	Create a CenterlineMask directly from another mask.
from_masks(*args, **kwargs)
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)
method	Method used to compute the mask.
shape
variables

__getitem__(var)

Implement slicing.

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

static from_Planform_and_FlowMask(_Planform, _FlowMask, **kwargs)

Create from a Planform and a FlowMask.

static from_array(_arr)

Create a CenterlineMask from an array.

Note

Instantiation with from_array will attempt to any data type (dtype) to boolean. This may have unexpected results. Convert your array to a boolean before using from_array to ensure the mask is created correctly.

Parameters:

_arr (ndarray) – The array with values to set as the mask. Can be any dtype but will be coerced to boolean.

static from_mask(*args, **kwargs)

Create a CenterlineMask directly from another mask.

Can take either an ElevationMask or LandMask and a FlowMask, OR just a ChannelMask, as input.

Note

finish docstring

Examples

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)

property method

Method used to compute the mask.

Returns:

method – Method name as string.

Return type:

str

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.

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