mapsplot.py 文件源码

def grid_density_gaussian_filter(data, size, resolution=None, smoothing_window=None):
    """Smoothing grid values with a Gaussian filter.

    :param [(float, float, float)] data: list of 3-dimensional grid coordinates
    :param int size: grid size
    :param int resolution: desired grid resolution
    :param int smoothing_window: size of the gaussian kernels for smoothing

    :return: smoothed grid values
    :rtype: numpy.ndarray
    """
    resolution = resolution if resolution else size
    k = (resolution - 1) / size
    w = smoothing_window if smoothing_window else int(0.01 * resolution)    # Heuristic
    imgw = (resolution + 2 * w)
    img = np.zeros((imgw, imgw))
    for x, y, z in data:
        ix = int(x * k) + w
        iy = int(y * k) + w
        if 0 <= ix < imgw and 0 <= iy < imgw:
            img[iy][ix] += z
    z = ndi.gaussian_filter(img, (w, w))                                    # Gaussian convolution
    z[z <= BLANK_THRESH] = np.nan                                           # Making low values blank
    return z[w:-w, w:-w]