utils.py 文件源码

def concave_hull(points, alpha, delunay_args=None):
    """Computes the concave hull (alpha-shape) of a set of points.
    """
    delunay_args = delunay_args or {
        'furthest_site': False,
        'incremental': False,
        'qhull_options': None
    }
    triangulation = Delaunay(np.array(points))
    alpha_complex = get_alpha_complex(alpha, points, triangulation.simplices)
    X, Y = [], []
    for s in triangulation.simplices:
        X.append([points[s[k]][0] for k in [0, 1, 2, 0]])
        Y.append([points[s[k]][1] for k in [0, 1, 2, 0]])
    poly = Polygon(list(zip(X[0], Y[0])))
    for i in range(1, len(X)):
        poly = poly.union(Polygon(list(zip(X[i], Y[i]))))
    return poly