spatial.GeometryFMLineSpectrum

spatial.GeometryFMLineSpectrum(
    self,
    node_coordinates,
    element_table,
    codes=None,
    projection='LONG/LAT',
    dfsu_type=None,
    element_ids=None,
    node_ids=None,
    validate=True,
    frequencies=None,
    directions=None,
    reindex=False,
)

Attributes

Name Description
boundary_codes Unique list of boundary codes.
boundary_polylines Lists of closed polylines defining domain outline.
codes Node codes of all nodes (0=water, 1=land, 2…=open boundaries).
directions Directional axis.
element_coordinates Center coordinates of each element.
frequencies Frequency axis.
is_2d Type is either mesh or Dfsu2D (2 horizontal dimensions).
is_geo Are coordinates geographical (LONG/LAT)?
is_layered Type is layered dfsu (3d, vertical profile or vertical column).
is_local_coordinates Are coordinates relative (NON-UTM)?
is_spectral Type is spectral dfsu (point, line or area spectrum).
is_tri_only Does the mesh consist of triangles only.
max_nodes_per_element The maximum number of nodes for an element.
n_directions Number of directions.
n_elements Number of elements.
n_frequencies Number of frequencies.
n_nodes Number of nodes.
projection The projection.
projection_string The projection string.
type_name Type name, e.g. Mesh, Dfsu2D.

Methods

Name Description
contains Test if a list of points are contained by mesh.
find_index Find a set of element indicies for a number of points or within an area.
find_nearest_elements Find index of nearest elements (optionally for a list).
get_2d_interpolant IDW interpolant for list of coordinates.
get_element_area Calculate the horizontal area of each element.
get_node_centered_data Convert cell-centered data to node-centered by pseudo-laplacian method.
get_overset_grid Get a 2d grid that covers the domain by specifying spacing or shape.
interp2d Interpolate spatially in data (2d only).
to_mesh Export geometry to new mesh file.
to_shapely Export mesh as shapely MultiPolygon.

contains

spatial.GeometryFMLineSpectrum.contains(points)

Test if a list of points are contained by mesh.

Parameters

Name Type Description Default
points array-like n-by-2 x,y-coordinates of n points to be tested required

Returns

Name Type Description
bool array True for points inside, False otherwise

find_index

spatial.GeometryFMLineSpectrum.find_index(
    x=None,
    y=None,
    coords=None,
    area=None,
)

Find a set of element indicies for a number of points or within an area.

The returned indices returned are the unique, unordered set of element indices that contain the points or area.

This method will return elements containing the argument points/area, which is not necessarily the same as the nearest.

Typically not called directly, but by Dataset/DataArray’s sel() method.

Parameters

Name Type Description Default
x float | np.ndarray | None X coordinate(s) (easting or longitude) None
y float | np.ndarray | None Y coordinate(s) (northing or latitude) None
coords np.array(float, float) As an alternative to specifying x, and y individually, the argument coords can be used instead. (x,y)-coordinates of points to be found, by default None None
area (float, float, float, float) Bounding box of coordinates (left lower and right upper) to be selected, by default None None

Returns

Name Type Description
np.array indicies of containing elements

Raises

Name Type Description
ValueError if any point is outside the domain

Examples

>>> g = dfs.geometry
>>> id = dfs.find_index(x=3.1, y=4.3)

See Also

isel : get subset geometry for specific indicies find_nearest_elements : find nearest instead of containing elements

find_nearest_elements

spatial.GeometryFMLineSpectrum.find_nearest_elements(
    x,
    y=None,
    n_nearest=1,
    return_distances=False,
)

Find index of nearest elements (optionally for a list).

Parameters

Name Type Description Default
x float | np.ndarray X coordinate(s) (easting or longitude) required
y float | np.ndarray | None Y coordinate(s) (northing or latitude) None
n_nearest int return this many (horizontally) nearest points for each coordinate set, default=1 1
return_distances bool should the horizontal distances to each point be returned? default=False False

Returns

Name Type Description
np.array element ids of nearest element(s)
(np.array, optional) horizontal distances

Examples

>>> g = dfs.geometry
>>> id = g.find_nearest_elements(3, 4)
>>> ids = g.find_nearest_elements([3, 8], [4, 6])
>>> ids = g.find_nearest_elements(xy)
>>> ids = g.find_nearest_elements(3, 4, n_nearest=4)
>>> ids, d = g.find_nearest_elements(xy, return_distances=True)

See Also

find_index : find element indicies for points or an area

get_2d_interpolant

spatial.GeometryFMLineSpectrum.get_2d_interpolant(
    xy,
    n_nearest=5,
    extrapolate=False,
    p=2,
    radius=None,
)

IDW interpolant for list of coordinates.

Parameters

Name Type Description Default
xy array - like x,y coordinates of new points required
n_nearest int number of nearest elements used for IDW, by default 5 5
extrapolate bool allow extrapolation, by default False False
p float power of inverse distance weighting, default=2 2
radius float | None an alternative to extrapolate=False, only include elements within radius None

Returns

Name Type Description
(np.array, np.array) element ids and weights

get_element_area

spatial.GeometryFMLineSpectrum.get_element_area()

Calculate the horizontal area of each element.

Returns

Name Type Description
np.array(float) areas in m2

get_node_centered_data

spatial.GeometryFMLineSpectrum.get_node_centered_data(data, extrapolate=True)

Convert cell-centered data to node-centered by pseudo-laplacian method.

Parameters

Name Type Description Default
data np.array(float) cell-centered data required
extrapolate bool allow the method to extrapolate, default:True True

Returns

Name Type Description
np.array(float) node-centered data

get_overset_grid

spatial.GeometryFMLineSpectrum.get_overset_grid(
    dx=None,
    dy=None,
    nx=None,
    ny=None,
    buffer=0.0,
)

Get a 2d grid that covers the domain by specifying spacing or shape.

Parameters

Name Type Description Default
dx float or (float, float) grid resolution in x-direction (or in x- and y-direction) None
dy float grid resolution in y-direction None
nx int number of points in x-direction, by default None, (the value will be inferred) None
ny int number of points in y-direction, by default None, (the value will be inferred) None
buffer float positive to make the area larger, default=0 can be set to a small negative value to avoid NaN values all around the domain. 0.0

Returns

Name Type Description
<mikeio.Grid2D> 2d grid

interp2d

spatial.GeometryFMLineSpectrum.interp2d(
    data,
    elem_ids,
    weights=None,
    shape=None,
)

Interpolate spatially in data (2d only).

Parameters

Name Type Description Default
data ndarray or list(ndarray) dfsu data required
elem_ids ndarray(int) n sized array of 1 or more element ids used for interpolation required
weights ndarray(float) weights with same size as elem_ids used for interpolation None
shape tuple[int, …] | None reshape output None

Returns

Name Type Description
ndarray or list(ndarray) spatially interped data

Examples

>>> ds = dfsu.read()
>>> g = dfs.get_overset_grid(shape=(50,40))
>>> elem_ids, weights = dfs.get_2d_interpolant(g.xy)
>>> dsi = dfs.interp2d(ds, elem_ids, weights)

to_mesh

spatial.GeometryFMLineSpectrum.to_mesh(outfilename)

Export geometry to new mesh file.

Parameters

Name Type Description Default
outfilename str path to file to be written required

to_shapely

spatial.GeometryFMLineSpectrum.to_shapely()

Export mesh as shapely MultiPolygon.

Returns

Name Type Description
shapely.geometry.MultiPolygon polygons with mesh elements