# !/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Filename: spectra.py
# Project: tools
# Author: Brian Cherinka
# Created: Sunday, 11th October 2020 3:15:12 pm
# License: BSD 3-clause "New" or "Revised" License
# Copyright (c) 2020 Brian Cherinka
# Last Modified: Sunday, 11th October 2020 3:15:12 pm
# Modified By: Brian Cherinka
from __future__ import print_function, division, absolute_import
import warnings
try:
import matplotlib.pyplot as plt
except ImportError:
plt = None
from astropy.io.registry import IORegistryError
from specutils import Spectrum1D
from typing import Type
from sdss_brain.core import Brain
from sdss_brain.exceptions import BrainNotImplemented, BrainMissingDependency
from sdss_brain.helpers import (sdss_loader, get_mapped_version, load_fits_file, parse_data_input,
load_from_url)
[docs]class Spectrum(Brain):
''' Base class for working with spectral data using specutils
Uses `specutils <https://specutils.readthedocs.io/en/stable/>`_ to load the
underlying spectral data into an Astropy Spectrum1D object, which is represented as an
nd-data array object.
Attributes
----------
spectrum : `~specutils.Spectrum1D`
An Astropy specutils Spectrum1D object
'''
spectrum: Type[Spectrum1D] = None
specutils_format: str = None
def _load_object_from_file(self, data=None) -> None:
self.data = data or load_fits_file(self.filename)
self.header = self.data['PRIMARY'].header
self._load_spectrum()
def _load_object_from_db(self, data=None) -> None:
raise BrainNotImplemented('This method must be implemented by the user')
def _load_object_from_api(self, data=None) -> None:
# for now, do a simple get request to grab the file into memory
self.data = data or load_from_url(self.get_full_path(url=True))
self.header = self.data['PRIMARY'].header
self._load_spectrum()
def _load_spectrum(self) -> None:
''' Load the `~specutils.Spectrum1D` object '''
try:
# check robustness of this to self.data/self.filename when specutils 1.1.1 is released
self.spectrum = Spectrum1D.read(self.data, format=self.specutils_format)
except IORegistryError:
warnings.warn('Could not load Spectrum1D for format '
f'{self.specutils_format}, {self.filename}')
[docs] def plot(self, *args, ax=None, x_label: str = 'Wavelength', y_label: str = 'Flux',
title: str = None, **kwargs):
""" A simple quick matplotlib plot of the spectrum
Create a quickplot matplotlib line profile plot for spectra
Parameters
----------
args : int|list, optional
for multi-dimensional spectra, the index to plot, by default None
ax : object, optional
An existing matplotlib Axes object by default None
x_label : str, optional
The x-axis plot label, by default 'Wavelength'
y_label : str, optional
The y-axis plot label, by default 'Flux'
title : str, optional
The plot title, by default None
Returns
-------
matplotlib.plt.Axes
The matplotlib Axes object
Raises
------
BrainMissingDependency
when matplotlib is not installed
"""
if not self.spectrum:
return
if not plt:
raise BrainMissingDependency("Package matplotlib not installed.")
if self.spectrum.flux.ndim > 1:
index = args
if not index:
raise ValueError('The spectrum is n-dimensional. You must specify a spectrum '
'index to plot.')
if not all([type(i) == int for i in index]):
raise ValueError('Input spectrum indices must be integers')
min_index = self.spectrum.flux.ndim - 1
index = index if isinstance(index, (tuple, list)) else [index] if type(index) == int else index
if len(index) < min_index:
raise ValueError(f'The spectrum has dimension={self.spectrum.flux.ndim}. '
f'You must specify a minimum of {min_index} indices')
if min_index == 1:
ii = index[0]
ydata = self.spectrum.flux[ii]
elif min_index == 2:
ii, jj = index
ydata = self.spectrum.flux[ii, jj]
else:
raise ValueError('plot cannot currently support spectral dimensions higher than 3')
else:
ydata = self.spectrum.flux
if not ax:
ax = plt.gca()
title = title or f'Object: {self.objectid or self.filename.stem}'
ax.plot(self.spectrum.wavelength, ydata, **kwargs)
ax.set_ylabel(f'{y_label} [{self.spectrum.flux.unit.to_string(format="latex_inline")}]')
ax.set_xlabel(f'{x_label} [{self.spectrum.wavelength.unit.to_string(format="latex_inline")}]')
ax.set_title(title)
return ax
# example of using a custom pattern in the sdss_loader
[docs]@sdss_loader(name='spec-lite', mapped_version='eboss:run2d',
pattern=r'(?P<plateid>\d{4,5})-(?P<mjd>\d{5})-(?P<fiberid>\d{1,4})')
class Eboss(Spectrum):
""" Class representing a single fiber SDSS spectra from BOSS/EBOSS
Parameters
----------
lite : bool
If True, loads the "spec-lite" spectral data. When False, loads
the "full" spectral data.Default is True.
"""
specutils_format: str = 'SDSS-III/IV spec'
def __init__(self, *args: str, lite: bool = True, **kwargs: str) -> None:
self.lite = lite
self.path_name = f'spec{"-lite" if lite else ""}'
super(Eboss, self).__init__(*args, **kwargs)
def __repr__(self):
old = super(Eboss, self).__repr__()
return old.replace('>', f', lite={self.lite}>')
# example of using a access keys to define the pattern in the sdss_loader
# setting a custom delimiter to "--" since APOGEE field names can have "-" in them.
[docs]@sdss_loader(name='apStar', defaults={'apstar': 'stars', 'prefix': 'ap'}, delimiter='--',
mapped_version='apogee:apred', order=['telescope', 'field', 'obj'])
class ApStar(Spectrum):
""" Class representing an APOGEE combined spectrum for a single star """
specutils_format: str = 'APOGEE apStar'
[docs]@sdss_loader(name='apVisit', defaults={'prefix': 'ap'}, delimiter='--',
mapped_version='apogee:apred', order=['telescope', 'field', 'plate', 'mjd', 'fiber'])
class ApVisit(Spectrum):
""" Class representing an APOGEE single visit spectrum for a given star """
specutils_format: str = 'APOGEE apVisit'
# example of overloading the methods manually
[docs]class AspcapStar(Spectrum):
""" Class representing an APOGEE spectrum for a single star with ASPCAP results """
specutils_format: str = 'APOGEE aspcapStar'
path_name: str = 'aspcapStar'
mapped_version: str = 'apogee'
def _parse_input(self, value):
# use the sdss_access keys to form the object id and parse it
keys = self.access.lookup_keys(self.path_name)
data = parse_data_input(value, keys=keys, delimiter='--',
order=['aspcap', 'telescope', 'field', 'obj'], )
return data
def _set_access_path_params(self):
# extract the apred version id based on the data release
apred = get_mapped_version(self.mapped_version, release=self.release, key='apred')
# set the path params using the instance attributes extracted from _parse_input
self.path_params = {'telescope': self.telescope, 'apred': apred,
'field': self.field, 'obj': self.obj, 'aspcap': self.aspcap}
