示例#1
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def extract(spectrum_data, x_range):
    ''' Extracts a region from a spectrum.

    Paramaters
    ----------
    spectrum_data: SpectrumData
      Contains the spectrum to be extracted.
    w_range: tuple
      A spectral coordinate range as in (wave1, wave2)

    Returns
    -------
    SpectrumData with extracted region.

    '''
    x = spectrum_data.x.data
    y = spectrum_data.y.data

    slice = (x >= x_range[0]) & (x < x_range[1])

    result = SpectrumData()
    result.set_x(x[slice], unit=spectrum_data.x.unit)
    result.set_y(y[slice], unit=spectrum_data.y.unit)

    return result
示例#2
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def read_image(image, flux_unit=None, dispersion_unit=None, **kwargs):
    """Read 1D image

    Parameters
    ----------
    image: FITS Image HDU

    Returns
    -------
    SpectrumData

    Notes
    -----
    Assumes ONLY 1D and that the WCS has the dispersion
    definition. If not, its just pixels.
    """
    if len(image.data.shape) > 1:
        raise RuntimeError('Attempting to read an image with more than one '
                           'dimension.')
    wcs = WCS(image.header)
    spectrum = SpectrumData()
    unit = flux_unit if flux_unit else DEFAULT_FLUX_UNIT
    spectrum.set_y(image.data, unit=unit)
    unit = wcs.wcs.cunit[0] if not dispersion_unit else dispersion_unit
    spectrum.set_x(wcs.all_pix2world(range(image.data.shape[0]), 1)[0],
                   unit=unit)

    return spectrum
示例#3
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def read_table(table,
               flux='flux', dispersion='wavelength',
               flux_unit=None, dispersion_unit=None):
    """Read FITS table

    Parameters
    ----------
    table: FITS table

    dispersion: str
                Name of column containing the dispersion axis.

    flux: str
          Name of column containing the flux axis.

    dispersion_unit: str
                     Unit of dispersion

    flux_unit: str
               Unit of flux

    Returns
    -------
    SpectrumData
    '"""
    if dispersion_unit is None:
        try:
            dispersion_unit = table.columns[table.names.index(dispersion.upper())].unit
            if dispersion_unit is None:
                raise ValueError
        except ValueError:
            dispersion_unit = DEFAULT_DISPERSION_UNIT
    if flux_unit is None:
        try:
            flux_unit = table.columns[table.names.index(flux.upper())].unit
            if flux_unit is None:
                raise ValueError
        except ValueError:
            flux_unit = DEFAULT_FLUX_UNIT

    spectrum = SpectrumData()
    spectrum.set_x(table[dispersion], unit=dispersion_unit)
    spectrum.set_y(table[flux], unit=flux_unit)

    return spectrum
示例#4
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def read_image(image, flux_unit=None, dispersion_unit=None, **kwargs):
    """Read 1D image

    Parameters
    ----------
    image: FITS Image HDU

    Returns
    -------
    SpectrumData

    Notes
    -----
    Assumes ONLY 1D and that the WCS has the dispersion
    definition. If not, its just pixels.
    """
    if len(image.data.shape) > 1:
        raise RuntimeError('Attempting to read an image with more than one '
                           'dimension.')
    wcs = WCS(image.header)
    spectrum = SpectrumData()
    unit = flux_unit if flux_unit else DEFAULT_FLUX_UNIT
    spectrum.set_y(image.data, unit=unit)
    unit = wcs.wcs.cunit[0] if not dispersion_unit else dispersion_unit
    spectrum.set_x(wcs.all_pix2world(range(image.data.shape[0]), 1)[0],
                   unit=unit)

    return spectrum
示例#5
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def extract(spectrum_data, x_range):
    ''' Extracts a region from a spectrum.

    Paramaters
    ----------
    spectrum_data: SpectrumData
      Contains the spectrum to be extracted.
    w_range: tuple
      A spectral coordinate range as in (wave1, wave2)

    Returns
    -------
    SpectrumData with extracted region.

    '''
    x = spectrum_data.x.data
    y = spectrum_data.y.data

    slice = (x >= x_range[0]) & (x < x_range[1])

    result = SpectrumData()
    result.set_x(x[slice], unit=spectrum_data.x.unit)
    result.set_y(y[slice], unit=spectrum_data.y.unit)

    return result
示例#6
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def read_table(table,
               flux='flux',
               dispersion='wavelength',
               flux_unit=None,
               dispersion_unit=None):
    """Read FITS table

    Parameters
    ----------
    table: FITS table

    dispersion: str
                Name of column containing the dispersion axis.

    flux: str
          Name of column containing the flux axis.

    dispersion_unit: str
                     Unit of dispersion

    flux_unit: str
               Unit of flux

    Returns
    -------
    SpectrumData
    '"""
    if dispersion_unit is None:
        try:
            dispersion_unit = table.columns[table.names.index(
                dispersion.upper())].unit
            if dispersion_unit is None:
                raise ValueError
        except ValueError:
            dispersion_unit = DEFAULT_DISPERSION_UNIT
    if flux_unit is None:
        try:
            flux_unit = table.columns[table.names.index(flux.upper())].unit
            if flux_unit is None:
                raise ValueError
        except ValueError:
            flux_unit = DEFAULT_FLUX_UNIT

    spectrum = SpectrumData()
    spectrum.set_x(table[dispersion], unit=dispersion_unit)
    spectrum.set_y(table[flux], unit=flux_unit)

    return spectrum
示例#7
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# Example usage
def print_results(wave, flux, converted_wave, converted_flux):
    for k in range(4):
        print(wave[k], "   ", converted_wave[k])
    for k in range(4):
        print(flux[k], "   ", converted_flux[k])


import test_data

if __name__ == "__main__":
    # real emission line from UV spectrum of NGC3516
    x, y, e = test_data.get_data()

    # test conversions from SpectrumData objects.
    sp_data = SpectrumData()
    sp_data.set_x(x, unit="Angstrom")
    sp_data.set_y(y, unit="erg.s-1.cm**-2.Angstrom-1")  # flam

    converter = UnitsConverter(u.micron, u.Jy)
    converter.convertSpectrumData(sp_data)

    print(sp_data.x.unit, "  ", sp_data.y.unit)
    for k in range(4):
        print(sp_data.x.data[k], "   ", sp_data.y.data[k])

    # test conversions from Quantity objects.
    wave = test_data.get_data()[0] * u.Unit('angstrom')
    flux = test_data.get_data()[1] * u.Unit("erg / (Angstrom cm2 s)")

    converter = UnitsConverter(u.micron, u.Jy)
示例#8
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# Example usage
def print_results(wave, flux, converted_wave, converted_flux):
    for k in range(4):
        print(wave[k], "   ", converted_wave[k])
    for k in range(4):
        print(flux[k], "   ", converted_flux[k])

import test_data

if __name__ == "__main__":
    # real emission line from UV spectrum of NGC3516
    x,y,e = test_data.get_data()


    # test conversions from SpectrumData objects.
    sp_data = SpectrumData()
    sp_data.set_x(x, unit="Angstrom")
    sp_data.set_y(y, unit="erg.s-1.cm**-2.Angstrom-1") # flam

    converter = UnitsConverter(u.micron, u.Jy)
    converter.convertSpectrumData(sp_data)

    print(sp_data.x.unit, "  ", sp_data.y.unit)
    for k in range(4):
        print(sp_data.x.data[k], "   ", sp_data.y.data[k])


    # test conversions from Quantity objects.
    wave = test_data.get_data()[0] * u.Unit('angstrom')
    flux = test_data.get_data()[1] * u.Unit("erg / (Angstrom cm2 s)")