WaveCoord¶
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class
mpdaf.obj.
WaveCoord
(hdr=None, crpix=1.0, cdelt=1.0, crval=1.0, cunit=Unit("Angstrom"), ctype='LINEAR', shape=None)[source]¶ Bases:
object
WaveCoord class manages world coordinates in spectral direction.
Parameters: hdr : astropy.fits.CardList
A FITS header. If hdr is not None, WaveCoord object is created from this header and other parameters are not used.
crpix : float
Reference pixel coordinates. 1.0 by default. Note that for crpix definition, the first pixel in the spectrum has pixel coordinates.
cdelt : float
Step in wavelength (1.0 by default).
crval : float
Coordinates of the reference pixel (0.0 by default).
cunit : u.unit
Wavelength unit (Angstrom by default).
ctype : string
Type of the coordinates.
shape : integer or None
Size of spectrum (no mandatory).
Attributes
shape (integer) Size of spectrum. wcs (astropy.wcs.WCS) Wavelength coordinates. Methods Summary
coord
([pixel, unit])Return the coordinate corresponding to pixel. copy
()Copie WaveCoord object in a new one and returns it. get_crpix
()CRPIX getter (reference pixel on the wavelength axis). get_crval
([unit])CRVAL getter (value of the reference pixel on the wavelength axis). get_ctype
()Return the type of wavelength coordinates. get_end
([unit])Return the value of the last pixel. get_range
([unit])Return the wavelength range [Lambda_min,Lambda_max]. get_start
([unit])Return the value of the first pixel. get_step
([unit])Return the step in wavelength. info
([unit])Print information. isEqual
(other)Return True if other and self have the same attributes. pixel
(lbda[, nearest, unit])Return the decimal pixel corresponding to the wavelength lbda. rebin
(factor)Rebin to a new coordinate system (in place). resample
(step, start[, unit])Resample to a new coordinate system. set_crpix
(x)CRPIX setter (reference pixel on the wavelength axis). set_crval
(x[, unit])CRVAL getter (value of the reference pixel on the wavelength axis). set_step
(x[, unit])Return the step in wavelength. to_header
([naxis, use_cd])Generate a astropy. Methods Documentation
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coord
(pixel=None, unit=None)[source]¶ Return the coordinate corresponding to pixel.
If pixel is None (default value), the full coordinate array is returned.
Parameters: pixel : int, array or None.
pixel value.
unit :
astropy.units.Unit
type of the wavelength coordinates
Returns: out : float or array of float
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get_crval
(unit=None)[source]¶ CRVAL getter (value of the reference pixel on the wavelength axis).
Parameters: unit :
astropy.units.Unit
type of the wavelength coordinates
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get_end
(unit=None)[source]¶ Return the value of the last pixel.
Parameters: unit :
astropy.units.Unit
type of the wavelength coordinates
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get_range
(unit=None)[source]¶ Return the wavelength range [Lambda_min,Lambda_max].
Parameters: unit :
astropy.units.Unit
type of the wavelength coordinates
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get_start
(unit=None)[source]¶ Return the value of the first pixel.
Parameters: unit :
astropy.units.Unit
type of the wavelength coordinates
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get_step
(unit=None)[source]¶ Return the step in wavelength.
Parameters: unit :
astropy.units.Unit
type of the wavelength coordinates
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pixel
(lbda, nearest=False, unit=None)[source]¶ Return the decimal pixel corresponding to the wavelength lbda.
If nearest=True; returns the nearest integer pixel.
Parameters: lbda : float or array
wavelength value.
nearest : bool
If nearest is True returns the nearest integer pixel in place of the decimal pixel.
unit :
astropy.units.Unit
type of the wavelength coordinates
Returns: out : float or integer
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rebin
(factor)[source]¶ Rebin to a new coordinate system (in place).
Parameters: factor : integer
Factor.
Returns: out : WaveCoord
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resample
(step, start, unit=None)[source]¶ Resample to a new coordinate system.
Parameters: start : float
New wavelength for the pixel 0.
step : float
New step.
unit :
astropy.units.Unit
type of the wavelength coordinates
Returns: out : WaveCoord
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set_crval
(x, unit=None)[source]¶ CRVAL getter (value of the reference pixel on the wavelength axis).
Parameters: x : float
value of the reference pixel on the wavelength axis
unit :
astropy.units.Unit
type of the wavelength coordinates
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set_step
(x, unit=None)[source]¶ Return the step in wavelength.
Parameters: x : float
Step value
unit :
astropy.units.Unit
type of the wavelength coordinates
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