def get_area_triangle(p1, p2, p3):
    """
    Get the area of the triangle with vertices in p1, p2 and p3

    Parameters
    ----------
    p1 : np.array
        point p1.
    p2 : np.array
        point p2.
    p3 : np.array
        point p3.

    Returns
    -------
    float
        area of triangle.

    """
    det_jac = (p1[0] - p3[0]) * (p2[1] - p3[1]) - (p2[0] - p3[0]) * (p1[1] - p3[1])
    return 0.5 * abs(det_jac)