示例#1
0
def _slice_from_path(x, y, data, attribute, slc):
    """
    Extract a PV-like slice from a cube

    :param x: An array of x values to extract (pixel units)
    :param y: An array of y values to extract (pixel units)
    :param data: :class:`~glue.core.data.Data`
    :param attribute: :claass:`~glue.core.data.Component`
    :param slc: orientation of the image widget that `pts` are defined on

    :returns: (slice, x, y)
              slice is a 2D Numpy array, corresponding to a "PV ribbon"
              cutout from the cube
              x and y are the resampled points along which the
              ribbon is extracted

    :note: For >3D cubes, the "V-axis" of the PV slice is the longest
           cube axis ignoring the x/y axes of `slc`
    """
    from glue.external.pvextractor import Path, extract_pv_slice
    p = Path(list(zip(x, y)))

    cube = data[attribute]
    dims = list(range(data.ndim))
    s = list(slc)
    ind = _slice_index(data, slc)

    cube_wcs = getattr(data.coords, 'wcs', None)

    # transpose cube to (z, y, x, <whatever>)
    def _swap(x, s, i, j):
        x[i], x[j] = x[j], x[i]
        s[i], s[j] = s[j], s[i]

    _swap(dims, s, ind, 0)
    _swap(dims, s, s.index('y'), 1)
    _swap(dims, s, s.index('x'), 2)
    cube = cube.transpose(dims)

    # slice down from >3D to 3D if needed
    s = [slice(None)] * 3 + [slc[d] for d in dims[3:]]
    cube = cube[s]

    # sample cube
    spacing = 1  # pixel
    x, y = [np.round(_x).astype(int) for _x in p.sample_points(spacing)]

    try:
        result = extract_pv_slice(cube, path=p, wcs=cube_wcs, order=0)
    except:  # sometimes pvextractor complains due to wcs. Try to recover
        result = extract_pv_slice(cube, path=p, wcs=None, order=0)

    from astropy.wcs import WCS
    data = result.data
    wcs = WCS(result.header)

    return data, x, y, wcs
示例#2
0
def _slice_from_path(x, y, data, attribute, slc):
    """
    Extract a PV-like slice from a cube

    :param x: An array of x values to extract (pixel units)
    :param y: An array of y values to extract (pixel units)
    :param data: :class:`~glue.core.data.Data`
    :param attribute: :claass:`~glue.core.data.Component`
    :param slc: orientation of the image widget that `pts` are defined on

    :returns: (slice, x, y)
              slice is a 2D Numpy array, corresponding to a "PV ribbon"
              cutout from the cube
              x and y are the resampled points along which the
              ribbon is extracted

    :note: For >3D cubes, the "V-axis" of the PV slice is the longest
           cube axis ignoring the x/y axes of `slc`
    """
    from glue.external.pvextractor import Path, extract_pv_slice
    p = Path(list(zip(x, y)))

    cube = data[attribute]
    dims = list(range(data.ndim))
    s = list(slc)
    ind = _slice_index(data, slc)

    cube_wcs = getattr(data.coords, 'wcs', None)

    # transpose cube to (z, y, x, <whatever>)
    def _swap(x, s, i, j):
        x[i], x[j] = x[j], x[i]
        s[i], s[j] = s[j], s[i]

    _swap(dims, s, ind, 0)
    _swap(dims, s, s.index('y'), 1)
    _swap(dims, s, s.index('x'), 2)
    cube = cube.transpose(dims)

    # slice down from >3D to 3D if needed
    s = [slice(None)] * 3 + [slc[d] for d in dims[3:]]
    cube = cube[s]

    # sample cube
    spacing = 1  # pixel
    x, y = [np.round(_x).astype(int) for _x in p.sample_points(spacing)]

    try:
        result = extract_pv_slice(cube, path=p, wcs=cube_wcs, order=0)
    except:  # sometimes pvextractor complains due to wcs. Try to recover
        result = extract_pv_slice(cube, path=p, wcs=None, order=0)

    from astropy.wcs import WCS
    data = result.data
    wcs = WCS(result.header)

    return data, x, y, wcs