Compute the intersection point of two lines

    Parameters
    ----------
    x = x4 array: x1, x2, x3, x4
    y = x4 array: y1, y2, y3, y4
    line 1 is defined by p1,p2
    line 2 is defined by p3,p4

    Returns
    -------
    Ix: x-coordinate of intersection
    Iy: y-coordinate of intersection

def line_line_intersect(x, y):
    """Compute the intersection point of two lines

    Parameters
    ----------
    x = x4 array: x1, x2, x3, x4
    y = x4 array: y1, y2, y3, y4
    line 1 is defined by p1,p2
    line 2 is defined by p3,p4

    Returns
    -------
    Ix: x-coordinate of intersection
    Iy: y-coordinate of intersection
    """
    A = x[0] * y[1] - y[0] * x[1]
    B = x[2] * y[3] - y[2] * x[4]
    C = (x[0] - x[1]) * (y[2] - y[3]) - (y[0] - y[1]) * (x[2] - x[3])

    Ix = (A * (x[2] - x[3]) - (x[0] - x[1]) * B) / C
    Iy = (A * (y[2] - y[3]) - (y[0] - y[1]) * B) / C
    return Ix, Iy