我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用astropy.units.Unit()。
def spectral_factor_hz_to_micron(wavelength): """ This function ... :param wavelength: :return: """ wavelength_unit = "micron" frequency_unit = "Hz" # Convert string units to Unit objects if isinstance(wavelength_unit, basestring): wavelength_unit = Unit(wavelength_unit) if isinstance(frequency_unit, basestring): frequency_unit = Unit(frequency_unit) conversion_factor_unit = wavelength_unit / frequency_unit # Calculate the conversion factor factor = (wavelength ** 2 / speed_of_light).to(conversion_factor_unit).value return 1. / factor # -----------------------------------------------------------------
def spectral_factor_hz_to_meter(wavelength): """ This function ... :return: """ wavelength_unit = "m" frequency_unit = "Hz" # Convert string units to Unit objects if isinstance(wavelength_unit, basestring): wavelength_unit = Unit(wavelength_unit) if isinstance(frequency_unit, basestring): frequency_unit = Unit(frequency_unit) conversion_factor_unit = wavelength_unit / frequency_unit # Calculate the conversion factor factor = (wavelength ** 2 / speed_of_light).to(conversion_factor_unit).value return 1./factor # -----------------------------------------------------------------
def get_quantity(self, element, name, default_unit=None): # Import Astropy here to avoid import errors for this module for users without an Astropy installation from astropy.units import Unit splitted = element.get(name).split() value = float(splitted[0]) try: unit = splitted[1] except IndexError: unit = default_unit # Create a quantity object if unit is not None: value = value * Unit(unit) return value # ----------------------------------------------------------------- ## This function sets the value of a certain parameter of the specified tree element from an Astropy quantity.
def set_quantity(self, element, name, value, default_unit=None): # Import Astropy here to avoid import errors for this module for users without an Astropy installation from astropy.units import Unit try: # If this works, assume it is a Quantity (or Angle) unit = value.unit # Works for Angles as well (str(angle) gives something that is not 'value + unit' to_string = str(value.to(value.unit).value) + " " + str(unit) except AttributeError: if default_unit is not None: to_string = str(value) + " " + str(Unit(default_unit)) else: to_string = str(value) # dimensionless quantity # Set the value in the tree element element.set(name, to_string) # -----------------------------------------------------------------
def get_cutout_range_for_galaxy(self, galaxy_name): """ This function ... :param galaxy_name: :return: """ # Find the index of the galaxy in the LEDA - WISE table index = tables.find_index(self.leda_wise_table, galaxy_name) # Get the RA and DEC ra = self.leda_wise_table["ra2000"][index] * Unit("deg") dec = self.leda_wise_table["de2000"][index] * Unit("deg") # Get the D25 d25_arcmin = self.leda_wise_table["d25"][index] if d25_arcmin < 6: width = .5 * Unit("deg") else: width = 1. * Unit("deg") # Return the RA, DEC and width (all in degrees) return ra, dec, width # -----------------------------------------------------------------
def unit(self, unit): """ This function ... :param unit: :return: """ # Convert string units to Astropy unit objects if isinstance(unit, basestring): unit = Unit(unit) # Loop over all frames for frame_name in self.frames: # Inform the user log.debug("Setting the unit of the " + frame_name + " frame to " + str(unit) + " ...") # Set the unit for this frame self.frames[frame_name].unit = unit # -----------------------------------------------------------------
def fwhms(self): """ This function ... :return: """ # Initialize a list to contain the fwhm of the fitted stars fwhms = [] # Loop over all stars for star in self.stars: # If the star contains a model, add the fwhm of that model to the list if star.has_model: fwhm_pix = star.fwhm * Unit("pix") fwhm_arcsec = fwhm_pix * self.frame.average_pixelscale.to("arcsec/pix") fwhms.append(fwhm_arcsec) # Return the list return fwhms # -----------------------------------------------------------------
def length(self): """ This function ... :return: """ dec_start = self.start.dec.to("deg").value dec_end = self.end.dec.to("deg").value dec_center = 0.5 * (dec_start + dec_end) ra_start = self.start.ra.to("deg").value ra_end = self.end.ra.to("deg").value # Calculate the actual RA and DEC distance in degrees ra_distance = abs(coordinates.ra_distance(dec_center, ra_start, ra_end)) dec_distance = abs(dec_end - dec_start) ra_span = ra_distance * Unit("deg") dec_span = dec_distance * Unit("deg") return math.sqrt(ra_span**2 + dec_span**2) # -----------------------------------------------------------------
def from_pixel(cls, circle, wcs): """ This function ... :param circle: :param wcs: :return: """ center = SkyCoordinate.from_pixel(circle.center, wcs) # Get the pixelscale radius = circle.radius * Unit("pix") * wcs.average_pixelscale # Create a new SkyCircle return cls(center, radius, meta=circle.meta) # -----------------------------------------------------------------
def from_pixel(cls, rectangle, wcs): """ This function ... :param rectangle: :param wcs: :return: """ center = SkyCoordinate.from_pixel(rectangle.center, wcs) # Get the pixelscale radius = rectangle.radius * Unit("pix") * wcs.average_pixelscale # Create a new SkyRectangle return cls(center, radius, rectangle.angle, meta=rectangle.meta) # -----------------------------------------------------------------
def __init__(self, wavelengths=None, transmissions=None): """ This function ... :param wavelengths: :param transmissions: :return: """ # Column names names = ["Wavelength", "Transmission"] # Create the table if wavelengths is None or transmissions is None: self.table = Table(names=names, dtype=('f8', 'f8')) else: self.table = tables.new([wavelengths, transmissions], names) # Set column units self.table["Wavelength"].unit = Unit("micron") # -----------------------------------------------------------------
def __init__(self, wavelengths=None, attenuations=None): """ This function ... :param wavelengths: :param attenuations: :return: """ # Column names names = ["Wavelength", "Attenuation"] # Create the table if wavelengths is None or attenuations is None: self.table = Table(names=names, dtype=('f8', 'f8')) else: self.table = tables.new([wavelengths, attenuations], names) # Set column units self.table["Wavelength"].unit = Unit("micron") # -----------------------------------------------------------------
def luminosity_for_filter(self, filter, unit="W/micron"): """ This function ... :param filter: :param unit: :return: """ # Convole the Sun SED over the filter transmission curve luminosity = filter.convolve(self.sed.wavelengths(unit="micron", asarray=True), self.sed.luminosities(unit="W/micron", asarray=True)) # also in W/micron luminosity = luminosity * Unit("W/micron") # Return the luminosity return luminosity.to(unit) # -----------------------------------------------------------------
def __init__(self): """ This function ... :return: """ # Attributes self.table = Table(names=["Observatory", "Instrument", "Band", "Wavelength", "Flux", "Error-", "Error+"], dtype=('S10', 'S10', 'S10', 'f8', 'f8', 'f8', 'f8')) self.table["Wavelength"].unit = Unit("micron") self.table["Flux"].unit = Unit("Jy") self.table["Error-"].unit = Unit("Jy") self.table["Error+"].unit = Unit("Jy") # -----------------------------------------------------------------
def luminosity_for_filter(self, filter, unit="W/micron"): """ This function ... :param filter: :param unit: :return: """ #luminosity = filter.integrate(self.sed["Wavelength"], self.sed["Luminosity"]) luminosity = filter.convolve(self.sed.wavelengths(unit="micron", asarray=True), self.sed.luminosities(unit="W/micron", asarray=True)) # also in W/micron luminosity = luminosity * Unit("W/micron") # Return the luminosity in the desired unit return luminosity.to(unit) # -----------------------------------------------------------------
def get_quantity(entry, default_unit=None): """ This function ... :param entry: :param default_unit: :return: """ splitted = entry.split() value = float(splitted[0]) try: unit = splitted[1] except IndexError: unit = default_unit # Create a quantity object and return it if unit is not None: value = value * Unit(unit) return value # -----------------------------------------------------------------
def spectral_factor(wavelength, wavelength_unit, frequency_unit): """ This function ... :param wavelength: :param wavelength_unit: :param frequency_unit: :return: """ # Convert string units to Unit objects if isinstance(wavelength_unit, basestring): wavelength_unit = u.Unit(wavelength_unit) if isinstance(frequency_unit, basestring): frequency_unit = u.Unit(frequency_unit) conversion_factor_unit = wavelength_unit / frequency_unit # Calculate the conversion factor return (wavelength**2 / speed_of_light).to(conversion_factor_unit).value # -----------------------------------------------------------------
def convert_sdss(self): """ This function ... :return: """ # Unit = nanomaggies # 1 nanomaggie = 3.613e-6 Jy # Conversion from nanomaggies to Jy (per pixel2) self.conversion_factor *= 3.613e-6 # Conversion from Jy per pixel2 to the target unit (MJy / sr) self.convert_from_jy() # -----------------------------------------------------------------
def project_azimuth_to_pa(azimuth, inclination): """ This function ... :param azimuth: :param inclination: """ # Get the azimuth angle and inclination in radians azimuth_radian = azimuth.to("radian").value i_radian = inclination.to("radian").value denominator = math.sqrt(math.cos(azimuth_radian)**2 * math.cos(i_radian)**2 + math.sin(azimuth_radian)**2) cos_pa = math.cos(azimuth_radian) * math.cos(i_radian) / denominator sin_pa = math.sin(azimuth_radian) / denominator pa_radian = math.atan2(sin_pa, cos_pa) * Unit("radian") return pa_radian.to("deg") # -----------------------------------------------------------------
def deproject_pa_to_azimuth(pa, inclination): """ This function ... :param pa: :param inclination: :return: """ # Get the PA and inclination in radians pa_radian = pa.to("radian").value i_radian = inclination.to("radian").value denominator = math.sqrt(math.cos(pa_radian)**2 + math.sin(pa_radian)**2 * math.cos(i_radian)**2) cos_azimuth = math.cos(pa_radian) / denominator sin_azimuth = math.sin(pa_radian) * math.cos(inclination) / denominator azimuth_radian = math.atan2(sin_azimuth, cos_azimuth) * Unit("radian") return azimuth_radian.to("deg") # -----------------------------------------------------------------
def fluxdensity_to_luminosity(fluxdensity, wavelength, distance): """ This function ... :param fluxdensity: :param wavelength: :param distance: :return: """ luminosity = (fluxdensity * 4. * math.pi * distance ** 2.).to("W/Hz") # 3 ways: #luminosity_ = luminosity.to("W/micron", equivalencies=spectral_density(wavelength)) # does not work luminosity_ = (speed_of_light * luminosity / wavelength**2).to("W/micron") luminosity = luminosity.to("W/Hz").value * spectral_factor_hz_to_micron(wavelength) * Unit("W/micron") #print(luminosity_, luminosity) # is OK! return luminosity # -----------------------------------------------------------------
def get_quantity(self, element, name, default_unit=None): # Import Astropy here to avoid import errors for this module for users without an Astropy installation from astropy.units import Unit prop = element.get(name) if prop.startswith("[") and prop.endswith("]"): prop = prop[1:-1].split(":")[1] splitted = prop.split() value = float(splitted[0]) try: unit = splitted[1] except IndexError: unit = default_unit # Create a quantity object if unit is not None: value = value * Unit(unit) return value # ----------------------------------------------------------------- # Overwrite the default implementation in SkiFile to incorporate labeled properties
def pixelscale(self): """ This function ... :return: """ result = utils.proj_plane_pixel_scales(self) # returns: A vector (ndarray) of projection plane increments corresponding to each pixel side (axis). # The units of the returned results are the same as the units of cdelt, crval, and cd for the celestial WCS # and can be obtained by inquiring the value of cunit property of the input WCS WCS object. x_pixelscale = result[0] * Unit("deg/pix") y_pixelscale = result[1] * Unit("deg/pix") # Return the pixel scale as an extent return Pixelscale(x_pixelscale, y_pixelscale) # -----------------------------------------------------------------
def from_file(cls, path, skiprows=0): """ This function ... :param path: :param skiprows: :return: """ # Create a new SED sed = cls() wavelength_column, luminosity_column = np.loadtxt(path, dtype=float, unpack=True, skiprows=skiprows) sed.table = tables.new([wavelength_column, luminosity_column], ["Wavelength", "Luminosity"]) sed.table["Wavelength"].unit = Unit("micron") sed.table["Luminosity"].unit = Unit("W/micron") # Return the SED return sed # -----------------------------------------------------------------
def setup(self, image): """ This function ... :param image: :return: """ # Call the setup function of the base class super(UnitConverter, self).setup() # Create a unit object self.target_unit = u.Unit(self.config.to_unit) # Set the image reference self.image = image # -----------------------------------------------------------------
def project_tilt_to_pa(tilt, inclination): """ This function ... :param tilt: :param inclination: :return: """ # Get the tilt angle and inclination in radians tilt_radian = tilt.to("radian").value i_radian = inclination.to("radian").value denominator = math.sqrt(math.sin(tilt_radian)**2 * math.sin(i_radian)**2 + math.cos(tilt_radian)**2) cos_pa = math.sin(tilt_radian) * math.sin(i_radian) / denominator sin_pa = math.cos(tilt_radian) / denominator pa_radian = math.atan2(sin_pa, cos_pa) * Unit("radian") return pa_radian.to("deg") # -----------------------------------------------------------------
def _make_quantity(data, unit): """ Get a LogQuantity if the a LogUnit is used rather than a regular Quantity. Parameters ---------- data: numpy.ndarray the data unit: ~astropy.unit.Unit or ~astropy.unit.LogUnit The data units Returns ------- ~astropy.unit.Quantity or ~astropy.unit.LogQuantity depending on the unit type """ if isinstance(unit, LogUnit): return LogQuantity(data, unit=unit) else: return Quantity(data, unit=unit)
def _custom_unit_changed(self): if self.custom_units is None: return unit = self.custom_units.text() if unit == '': self.label_status.setText('') else: try: u.Unit(unit) except: self.label_status.setText('Invalid units') self.label_status.setStyleSheet('color: red') else: self.label_status.setText('Valid units') self.label_status.setStyleSheet('color: green')
