dfsu.DfsuSpectral

dfsu.DfsuSpectral(self, filename)

Attributes

Name	Description
deletevalue	File delete value.
directions	Directional axis.
end_time	File end time.
frequencies	Frequency axis.
geometry	Geometry.
items	List of items.
n_directions	Number of directions.
n_frequencies	Number of frequencies.
n_items	Number of items.
n_timesteps	Number of time steps.
start_time	File start time.
timestep	Time step size in seconds.

Methods

Name	Description
calc_Hm0_from_spectrum	Calculate significant wave height (Hm0) from spectrum.
read	Read data from a spectral dfsu file.

calc_Hm0_from_spectrum

dfsu.DfsuSpectral.calc_Hm0_from_spectrum(spectrum, tail=True)

Calculate significant wave height (Hm0) from spectrum.

Parameters

Name	Type	Description	Default
spectrum	(np.ndarray, DataArray)	frequency or direction-frequency spectrum	required
tail	bool	Should a parametric spectral tail be added in the computations? by default True	`True`

Returns

Name	Type	Description
	np.ndarray	significant wave height values

read

dfsu.DfsuSpectral.read(
    items=None,
    time=None,
    elements=None,
    nodes=None,
    area=None,
    x=None,
    y=None,
    keepdims=False,
    dtype=np.float32,
)

Read data from a spectral dfsu file.

Parameters

Name	Type	Description	Default
items	str \| int \| Sequence[str \| int] \| None	Read only selected items, by number (0-based), or by name	`None`
time	int \| str \| slice \| None	Read only selected time steps, by default None (=all)	`None`
keepdims	bool	When reading a single time step only, should the time-dimension be kept in the returned Dataset? by default: False	`False`
area	tuple[float, float, float, float] \| None	Read only data inside (horizontal) area (spectral area files only) given as a bounding box (tuple with left, lower, right, upper) or as list of coordinates for a polygon, by default None	`None`
x	float \| None	Read only data for elements containing the (x,y) points(s), by default None	`None`
y	float \| None	Read only data for elements containing the (x,y) points(s), by default None	`None`
elements	Sequence[int] \| np.ndarray \| None	Read only selected element ids (spectral area files only)	`None`
nodes	Sequence[int] \| np.ndarray \| None	Read only selected node ids (spectral line files only)	`None`
dtype	Any	Data type to read. Default is np.float32	`np.float32`

Returns

Name	Type	Description
	Dataset	A Dataset with dimensions [t,elements/nodes,frequencies,directions]

Examples

>>> mikeio.read("tests/testdata/spectra/line_spectra.dfsu")
<mikeio.Dataset>
dims: (time:4, node:10, direction:16, frequency:25)
time: 2017-10-27 00:00:00 - 2017-10-27 05:00:00 (4 records)
geometry: DfsuSpectral1D (9 elements, 10 nodes)
items:
  0:  Energy density <Wave energy density> (meter pow 2 sec per deg)

>>> mikeio.read("tests/testdata/spectra/area_spectra.dfsu", time=-1)
<mikeio.Dataset>
dims: (element:40, direction:16, frequency:25)
time: 2017-10-27 05:00:00 (time-invariant)
geometry: DfsuSpectral2D (40 elements, 33 nodes)
items:
  0:  Energy density <Wave energy density> (meter pow 2 sec per deg)