landlab.graph.quantity.of_link¶

get_angle_of_link(graph, out=None)[source]¶

Get angles of links in a graph.

Parameters:

graph (Graph) – A Graph.

Returns:

ndarray of float – Angle of each link as measured in radians from link tail to head.
out (ndarray of float, optional) – Buffer to place output.

Examples

>>> import numpy as np
>>> from landlab.graph import UniformRectilinearGraph
>>> from landlab.graph.quantity.of_link import get_angle_of_link

>>> graph = UniformRectilinearGraph((2, 2))
>>> get_angle_of_link(graph) * 180.0 / np.pi
array([  0.,  90.,  90.,   0.])

>>> angles = np.empty(graph.number_of_links, dtype=float)
>>> rtn = get_angle_of_link(graph, out=angles)
>>> angles is rtn
True

get_length_of_link(graph)[source]¶

get_midpoint_of_link(graph, out=None)[source]¶

Get xy position of the midpoint of links.

Parameters:

graph (Graph) – A Graph.
out (ndarray of float, optional) – Buffer to place output.

Returns:

Coordinates of link midpoints.

Return type:

ndarray of float, shape (n_links, 2)

Examples

>>> import numpy as np
>>> from landlab.graph import UniformRectilinearGraph
>>> from landlab.graph.quantity.of_link import get_midpoint_of_link

>>> graph = UniformRectilinearGraph((2, 2))
>>> get_midpoint_of_link(graph)
array([[0.5, 0. ],
       [0. , 0.5],
       [1. , 0.5],
       [0.5, 1. ]])

>>> points = np.empty((graph.number_of_links, 2), dtype=float)
>>> rtn = get_midpoint_of_link(graph, out=points)
>>> points is rtn
True