|
casa
$Rev:20696$
|
|
casa
$Rev:20696$
|
Functions | |
| def | sdbaseline |
| def sdbaseline.sdbaseline | ( | infile = '', |
|
antenna = 0, |
|||
fluxunit = '', |
|||
telescopeparm = '', |
|||
specunit = '', |
|||
restfreq = '', |
|||
frame = '', |
|||
doppler = '', |
|||
scanlist = [], |
|||
field = '', |
|||
iflist = [], |
|||
pollist = [], |
|||
tau = 0.0, |
|||
masklist = [], |
|||
maskmode = '', |
|||
thresh = 5.0, |
|||
avg_limit = 4, |
|||
edge = [0], |
|||
blfunc = 'poly', |
|||
order = 5, |
|||
npiece = 2, |
|||
applyfft = True, |
|||
fftmethod = 'fft', |
|||
fftthresh = 3.0, |
|||
addwn = [0], |
|||
rejwn = [], |
|||
clipthresh = 3.0, |
|||
clipniter = 0, |
|||
verify = False, |
|||
verbose = True, |
|||
bloutput = True, |
|||
blformat = '', |
|||
showprogress = True, |
|||
minnrow = 1000, |
|||
outfile = '', |
|||
outform = 'ASAP', |
|||
overwrite = False, |
|||
plotlevel = 0 |
|||
| ) |
ASAP SD task: fit/subtract a spectral baseline
Keyword arguments:
infile -- name of input SD dataset
antenna -- antenna name or id (only effective for MS input).
fluxunit -- units for line flux
options: 'K','Jy',''
default: '' (keep current fluxunit)
WARNING: For GBT data, see description below.
>>> fluxunit expandable parameter
telescopeparm -- the telescope characteristics
options: (str) name or (list) list of gain info
default: '' (none set)
example: if telescopeparm='', it tries to get the telescope
name from the data.
Full antenna parameters (diameter,ap.eff.) known
to ASAP are
'ATPKSMB', 'ATPKSHOH', 'ATMOPRA', 'DSS-43',
'CEDUNA','HOBART'. For GBT, it fixes default fluxunit
to 'K' first then convert to a new fluxunit.
telescopeparm=[104.9,0.43] diameter(m), ap.eff.
telescopeparm=[0.743] gain in Jy/K
telescopeparm='FIX' to change default fluxunit
see description below
specunit -- units for spectral axis
options: (str) 'channel','km/s','GHz','MHz','kHz','Hz',''
default: '' (=current)
example: this will be the units for masklist
>>> specunit expandable parameters
restfreq -- rest frequency
available type includes float, int, string, list of float,
list of int, list of string, and list of dictionary. the
default unit of restfreq in case of float, int, or string
without unit is Hz. string input can be a value only
(treated as Hz) or a value followed by unit for which 'GHz',
'MHz','kHz',and 'Hz' are available.
a list can be used to set different rest frequencies for
each IF. the length of list input must be nIF. dictionary
input should be a pair of molecule name and frequency with
keys of 'name' and 'value', respectively. values in the
dictionary input follows the same manner as for single
float or string input.
example: 345.796
'1420MHz'
[345.8, 347.0, 356.7]
['345.8MHz', '347.0MHz', '356.7MHz']
[{'name':'CO','value':345}]
frame -- frequency frame for spectral axis
options: (str) 'LSRK','REST','TOPO','LSRD','BARY',
'GEO','GALACTO','LGROUP','CMB'
default: currently set frame in scantable
WARNING: frame='REST' not yet implemented
doppler -- doppler mode
options: (str) 'RADIO','OPTICAL','Z','BETA','GAMMA'
default: currently set doppler in scantable
scanlist -- list of scan numbers to process
default: [] (use all scans)
example: [21,22,23,24]
this selection is in addition to field, iflist, and pollist
field -- selection string for selecting scans by name
default: '' (no name selection)
example: 'FLS3a*'
this selection is in addition to scanlist, iflist, and pollist
iflist -- list of IF id numbers to select
default: [] (use all IFs)
example: [15]
this selection is in addition to scanlist, field, and pollist
pollist -- list of polarization id numbers to select
default: [] (use all polarizations)
example: [1]
this selection is in addition to scanlist, field, and iflist
tau -- atmospheric optical depth
default: 0.0 (no correction)
masklist -- list or string of mask regions to INCLUDE in BASELINE fit
a string masklist allows per IF selection of channels.
default: [] (entire spectrum)
example: [[1000,3000],[5000,7000]]
'0:1000~3000;5000~7000, 1:200~350;450~600'
when maskmode is 'auto' or 'interact', this mask
will be applied first before fitting as base mask
maskmode -- mode of setting additional channel masks
options: (str) 'auto','list','interact'
default: 'auto'
example: maskmode='auto' runs linefinder to detect line regions
to be excluded from fitting. this mode requires three
expandable parameters: thresh, avg_limit, and edge.
USE WITH CARE! May need to tweak the expandable parameters.
maskmode='list' uses the given masklist only: no additional
masks applied.
maskmode='interact' allows users to manually modify the
mask regions by dragging mouse on the spectrum plotter GUI.
use LEFT or RIGHT button to add or delete regions,
respectively.
>>> maskmode expandable parameters
thresh -- S/N threshold for linefinder
default: 5
example: a single channel S/N ratio above which the channel is
considered to be a detection
avg_limit -- channel averaging for broad lines
default: 4
example: a number of consecutive channels not greater than
this parameter can be averaged to search for broad lines
edge -- channels to drop at beginning and end of spectrum
default: 0
example: [1000] drops 1000 channels at beginning AND end
[1000,500] drops 1000 from beginning and 500 from end
Note: For bad baselines threshold should be increased,
and avg_limit decreased (or even switched off completely by
setting this parameter to 1) to avoid detecting baseline
undulations instead of real lines.
blfunc -- baseline model function
options: (str) 'poly','chebyshev','cspline','sinusoid'
default: 'poly'
example: blfunc='poly' uses a single polynomial line of
any order which should be given as an expandable
parameter 'order' to fit baseline.
blfunc='chebyshev' uses Chebyshev polynomials.
blfunc='cspline' uses a cubic spline function, a piecewise
cubic polynomial having C2-continuity (i.e., the second
derivative is continuous at the joining points).
blfunc='sinusoid' uses a combination of sinusoidal curves.
>>> blfunc expandable parameters
order -- order of baseline polynomial
options: (int) (<0 turns off baseline fitting)
default: 5
example: typically in range 2-9 (higher values
seem to be needed for GBT)
npiece -- number of the element polynomials of cubic spline curve
options: (int) (<0 turns off baseline fitting)
default: 2
applyfft -- automatically set wave numbers of sinusoidal functions
for fitting by applying some method like FFT.
options: (bool) True, False
default: True
fftmethod -- method to be used when applyfft=True. Now only
'fft' is available and it is the default.
fftthresh -- threshold to select wave numbers to be used for
sinusoidal fitting. both (float) and (str) accepted.
given a float value, the unit is set to sigma.
for string values, allowed formats include:
'xsigma' or 'x' (= x-sigma level. e.g., '3sigma'), or
'topx' (= the x strongest ones, e.g. 'top5').
default is 3.0 (unit: sigma).
addwn -- additional wave number(s) of sinusoids to be used
for fitting.
(list) and (int) are accepted to specify every
wave numbers. also (str) can be used in case
you need to specify wave numbers in a certain range,
e.g., 'a-b' (= a, a+1, a+2, ..., b-1, b),
'<a' (= 0,1,...,a-2,a-1),
'>=a' (= a, a+1, ... up to the maximum wave
number corresponding to the Nyquist
frequency for the case of FFT).
default: [0] (i.e., constant is subtracted at least)
rejwn -- wave number(s) of sinusoid NOT to be used for fitting.
can be set just as addwn but has higher priority:
wave numbers which are specified both in addwn
and rejwn will NOT be used.
default: []
clipthresh -- clipping threshold for iterative fitting
default: 3
clipniter -- maximum iteration number
default: 0 (no iteration, i.e., no clipping)
verify -- verify the results of baseline fitting
options: (bool) True,False
default: False
NOTE: Currently available only when blfunc='poly'
WARNING: Currently this just asks whether you accept
the displayed fit and if not, continues
without doing any baseline fit.
verbose -- output fitting results to logger
default: True
example: If False, the fitting results including coefficients,
residual rms, etc., are not output to the CASA logger,
while the processing speed gets faster
bloutput -- output fitting results to a text file
default: True
example: If False, the fitting results including coefficients,
residual rms, etc., are not output to a text file
(<outfile>_blparam.txt), while the processing
speed gets faster
blformat -- format of the logger output and text file specified with bloutput
options: '', 'csv'
default: '' (same as in the past, easy to read but huge)
showprogress -- show progress status for large data
default: True
minnrow -- minimum number of input spectra to show progress status
default: 1000
outfile -- Name of output file
default: '' (<infile>_bs)
outform -- format of output file
options: 'ASCII','SDFITS','MS','ASAP'
default: 'ASAP'
example: the ASAP format is easiest for further sd
processing; use MS for CASA imaging.
If ASCII, then will append some stuff to
the outfile name
overwrite -- overwrite the output file if already exists
options: (bool) True,False
default: False
WARNING: if outform='ASCII', this parameter is ignored
plotlevel -- control for plotting of results
options: (int) 0=none, 1=some, 2=more, <0=hardcopy
default: 0 (no plotting)
example: plotlevel<0 as abs(plotlevel), e.g.
-1 => hardcopy of final plot (will be named
<outfile>_bspec.eps)
WARNING: be careful plotting in fsotf mode!
DESCRIPTION:
Task sdbaseline performs baseline fitting/removal for single-dish spectra.
The fit parameters, terms and rms of base-line are saved to an ascii
file, '<outfile>_blparam.txt'.
ASAP recognizes the data of the "AT" telescopes, but currently
does not know about the GBT or any other telescope. This task
does know about GBT. Telescope name is obtained from the data.
If you wish to change the fluxunit (see below), and telescopeparm='',
for the AT telescopes it will use internal telescope parameters for
flux conversion. For GBT, it will use an approximate aperture
efficiency conversion. If you give telescopeparm a list ,
then if the list has a single float it is assumed to
be the gain in Jy/K, if two or more elements they are assumed
to be telescope diameter (m) and aperture efficiency
respectively.
Note that sdbaseline assumes that the fluxunit is set correctly in
the data already. If not, then set telescopeparm='FIX' and it
will set the default units to fluxunit without conversion.
NOTE: If the data in infile is an ms from GBT and the default flux
unit is missing and this task automatically fixes the default fluxunit
to 'K' before the conversion.
WARNING for the GBT raw SDFITS format data as input:
SDtasks are able to handle GBT raw SDFITS format data since the
data filler is available. However, the functionality is not well
tested yet, so that there may be unknown bugs. Definition at line 13 of file sdbaseline.py.
References task_sdbaseline.sdbaseline(), and vla_uvfits_line_sf.verify.
1.8.0