3. polygon

Module for defining the class related to a Polygon and to verify what points are inside it.

class polygon.Polygon(coordinates)

Bases: object

Creates an instance of an object that defines a two dimension polygon.

Polygon(coordinates)

coordinates

Coordinates of vertices of the polygon.

Type:(n, 2) numpy.ndarray

Note

The class Polygon requires numpy and matplotlib.

Examples

>>> from numpy import array
>>> from pybimstab.polygon import Polygon
>>> coords = array([[0. , 1. , 1. , 0. ], [0. , 0. , 1.5, 1.5]])
>>> polygon = Polygon(coordinates=coords)
>>> polygon.__dict__
{'coordinates': array([[0. , 1. , 1. , 0. ],
                       [0. , 0. , 1.5, 1.5]])}

isinside(x, y, meshgrid=False, want2plot=False)

Method to know if the point(s) (x, y) is inside of the instanced polygon.

x and y could be iterable structures, even, they could define a meshgrid.

Parameters:

• x (int, float or (n, ) numpy.ndarray) – abscissa of the point(s) to check if is/are inside the polygon.
• y (int, float or (n, ) numpy.ndarray) – ordinate of the point(s) to check if is/are inside the polygon.
• meshgrid (bool) – variable to creck if x and y define a grid. The default value is False.
• want2plot (bool) – variable to creck if a plot is wanted. The default value is False.

Returns:

Array of boolean values where True means that the point is inside and False to points that is outside of the polygon.

Return type:

numpy.ndarray

Note

The method isinside does not work properly for points on the boundaries of the polygon.

Examples

>>> from numpy import array
>>> from pybimstab.polygon import Polygon
>>> coords = array([[0. , 1. , 1. , 0. ], [0. , 0. , 1.5, 1.5]])
>>> x, y = 0.5, 2
>>> polygon = Polygon(coordinates=coords)
>>> polygon.isinside(x=x, y=y, meshgrid=False, want2plot=True)
array([True], dtype=bool)

example script.

>>> from numpy import array
>>> from pybimstab.polygon import Polygon
>>> coords = array([[0, 1, 1, 0.], [0, 0, 1.5, 1.5]])
>>> x = array([0.3, 0.5, 0.7, 1.2, 1.0])
>>> y = array([0.6, 1., 1.4, 2.4, 0])
>>> polygon = Polygon(coordinates=coords)
>>> polygon.isinside(x=x, y=y, meshgrid=False, want2plot=True)
array([True, True, True, False, False], dtype=bool)

example script.

>>> from numpy import array
>>> from pybimstab.polygon import Polygon
>>> coords = array([[0, 1, 1, 0.], [0, 0, 1.5, 1.5]])
>>> x = array([0.3, 0.5, 0.7, 1.2, 1.0])
>>> y = array([0.6, 1., 1.4, 2.4, 0])
>>> polygon = Polygon(coordinates=coords)
>>> polygon.isinside(x=x, y=y, meshgrid=True, want2plot=True)
array([[ True,  True,  True, False,  True],
       [ True,  True,  True, False,  True],
       [ True,  True,  True, False,  True],
       [False, False, False, False, False],
       [False, False, False, False, False]], dtype=bool)

example script.

>>> import numpy as np
>>> from pybimstab.polygon import Polygon
>>> xC = [np.cos(theta) for theta in np.linspace(0, 2*np.pi, 100)]
>>> yC = [np.sin(theta) for theta in np.linspace(0, 2*np.pi, 100)]
>>> coords = np.array([xC, yC])
>>> np.random.seed(123)
>>> x = np.random.uniform(-1, 1, 100)
>>> y = np.random.uniform(-1, 1, 100)
>>> polygon = Polygon(coordinates=coords)
>>> polygon.isinside(x=x, y=y, meshgrid=False, want2plot=True);

example script.