spatial.GeometryFM2D

spatial.GeometryFM2D(self, node_coordinates, element_table, codes=None, projection='LONG/LAT', dfsu_type=DfsuFileType.Dfsu2D, element_ids=None, node_ids=None, validate=True, 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)
element_coordinates	Center coordinates of each element
geometry2d	Return self
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_elements	Number of elements
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	interp spatially in data (2d only)
isel	export a selection of elements to a new geometry
to_mesh	Export geometry to new mesh file
to_shapely	Export mesh as shapely MultiPolygon

contains

spatial.GeometryFM2D.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

Type	Description
bool array	True for points inside, False otherwise

find_index

spatial.GeometryFM2D.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 \| numpy.numpy.ndarray \| None	X coordinate(s) (easting or longitude)	`None`
`y`	float \| numpy.numpy.ndarray \| None	Y coordinate(s) (northing or latitude)	`None`
`coords`	numpy.numpy.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

Type	Description
numpy.numpy.array	indicies of containing elements

Raises

Type	Description
ValueError	if any point is outside the domain

Examples

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

find_nearest_elements

spatial.GeometryFM2D.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 \| numpy.numpy.ndarray	X coordinate(s) (easting or longitude)	required
`y`	float \| numpy.numpy.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

Type	Description
numpy.numpy.array	element ids of nearest element(s)
(numpy.numpy.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)

get_2d_interpolant

spatial.GeometryFM2D.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

Type	Description
(numpy.numpy.array, numpy.numpy.array)	element ids and weights

get_element_area

spatial.GeometryFM2D.get_element_area()

Calculate the horizontal area of each element.

Returns

Type	Description
numpy.numpy.array(float)	areas in m2

get_node_centered_data

spatial.GeometryFM2D.get_node_centered_data(data, extrapolate=True)

convert cell-centered data to node-centered by pseudo-laplacian method

Parameters

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

Returns

Type	Description
numpy.numpy.array(float)	node-centered data

get_overset_grid

spatial.GeometryFM2D.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

Type	Description
<mikeio.Grid2D>	2d grid

interp2d

spatial.GeometryFM2D.interp2d(data, elem_ids, weights=None, shape=None)

interp 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`	typing.Tuple[int, …] \| None	reshape output	`None`

Returns

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)

isel

spatial.GeometryFM2D.isel(idx, keepdims=False, **kwargs)

export a selection of elements to a new geometry

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

Parameters

Name	Type	Description	Default
`idx`	collection(int)	collection of element indicies	required
`keepdims`	bool	Should the original Geometry type be kept (keepdims=True) or should it be reduced e.g. to a GeometryPoint2D if possible (keepdims=False), by default False	`False`

Returns

Type	Description
Geometry	geometry subset

to_mesh

spatial.GeometryFM2D.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.GeometryFM2D.to_shapely()

Export mesh as shapely MultiPolygon

Returns

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

spatial.GeometryFM2D

Attributes

Methods

contains

Parameters

Returns

find_index

Parameters

Returns

Raises

Examples

See Also

find_nearest_elements

Parameters

Returns

Examples

See Also

get_2d_interpolant

Parameters

Returns

get_element_area

Returns

get_node_centered_data

Parameters

Returns

get_overset_grid

Parameters

Returns

interp2d

Parameters

Returns

Examples

isel

Parameters

Returns

See Also

to_mesh

Parameters

to_shapely

Returns