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5.1.2 sd.scantable - Tool

Representation of single-dish data format
Description

The scantable is a representation of the Scantable, which is a data format designed properly for single-dish data. The scantable is implemented as CASA table so that it is possible to access data via table tool. On the other hand, the scantable has its own functions to get/set some data. In addition to the simple setter/getter and utility functions, the scantable has some data reduction function such as calibration, baseline fitting, etc.

The ’insitu’ option often appears in the functions. This parameter controls if a certain operation is applied to this scantable (true) or return another scantable that is a result of the operation (false). In former case, the original scantable loaded will be lost although the data on disk will be kept. The default value of the option depends on sd.rcParams dictionary. See sd.list_rcparameters for details about sd.rcParams.

The constructor takes several arguments that handles some of optional behavior of it. The getpt and antenna arguments are only effective if file specified by filename argument is Measurement Set format.

Definition

A documentation for detailed definition of the Scantable will be prepared by ATNF.

Arguments





Inputs

filename

Name of an input file, or a reference to an existing scantable (advanced)

allowed:

string, scantable

Default:

average

Average all integrations within a scan on read

allowed:

bool

Default:

None (taken from scantable.autoaverage attribute of rc parameters)

unit

Brightness unit. It must be consistent with K or Jy. It overrides the default value or replaces the value in existing scantables

allowed:

string

Default:

None

getpt

Measurement Set input data only. If True, all pointing data are filled.

allowed:

bool

Default:

False

antenna

Measurement Set input data only. Antenna selection by ID or name

allowed:

string, integer

Default:

” (first antenna in the ANTENNA table)

parallactify

Indicate that the data had been parallactified.

allowed:

bool

Default:

None (taken from scantable.parallactify attribute of rc parameters)





Example

     # create scantable from the data from the second antenna in Measurement Set  
     s=sd.scantable(’sddata.ms’,average=False,getpt=True,antenna=1)

Methods

add Return a scan where all spectra have the offset added
auto_cspline_baseline Perform automatic line finding and baseline subtraction using cubic spline function
auto_poly_baseline Perform automatic line finding and baseline subtraction using polynomial function
auto_sinusoid_baselinePerform automatic line finding and baseline subtraction using sinusoidal function
auto_quotient Automatic quotient for coordinated scans
average_beam Average beams together for multi-beam observation
average_pol Average polarizations together
average_time Return time average of a scan
bin Perform binning of spectra
chan2data Return channel/frequency/velocity and spectral value
clip Flag data by its spectral value
convert_flux Return a scan where all spectra are converted to Jy or K
convert_pol Convert data to a different polarization type
copy Return a copy of this scantable
create_mask Return a bool array based on [min,max] windows
cspline_baseline Perform a baseline subtraction using cubic spline function
drop_scan Return a new scantable where the specified scan number(s) dropped
flag Apply FFT to the spectra
flag Flag selected data using specified mask (channel based flag)
flag_nans Flag NaN values
flag_row Flag spectra based on specified rows (row based flag)
freq_align Perform frequency alignment
freq_switch Apply frequency switching to the data
gain_el Apply gain-elevation correction based on user-provided data
get_abcissa Get the abcissa values
get_antennaname Get antenna name
get_azimuth Get a list of azimuth during the observation
get_column_namesGet a list of column names in the main table
get_coordinate Return the spectral coordinate for a given row as a coordinate object
get_direction Get a list of positions on the sky as a string
get_directionval Get a list of positions on the sky as a float
get_elevation Get a list of elevation during the observation
get_fit Get the stored fits for a row in scantable
get_fluxunit Get a flux unit
get_inttime Get a list of integration times for the observation
get_mask Get mask for the specified row as a bool list
get_mask_indices Compute a lists of mask start/end indices from the given bool array
get_masklist Compute a list of mask windows from the given bool array
get_parangle Get a list of parallactic angles for the observation
get_restfreqs Get the rest frequency(s) stored in the scantable
get_rms Calculate rms of the spectrum
get_row Return a scantable with single row
get_row_selectorReturn a selector object that only selects target row
get_scan Return a specified scan(s) specified by scan number or source name
get_selection Get current selection that is currently set on this scantable
get_sourcename Get a list of source names for the observation
get_spectrum Get the spectrum for the current row
get_time Get a list of time stamps for the observation
get_tsys Get a list of system temperatures
get_unit Get the default unit of spectral axis
get_weather Get the weather informations
getbeam Get beam number of the given row
getbeamnos Get a list of beam numbers in the scantable
getcycle Get cycle number of the given row
getif Get IF number of the given row
getifnos Get a list of IF nubers in the scantable
getmolnos Get a list of molecule ids in the scantable
getpol Get polarization number of the given row
getpolnos Get a list of polarization numbers in the scantable
getscan Get scan number of the given row
getscannos Get a list of scan numbers in the scantable
history Print a history
invert_phase Invert the phase of the complex polarization
lag_flag Perform Fourier filtering on the spectra
mx_quotient Form a quotient using ”off” beams when observing in ”MX” mode
nbeam Return a number of beams
nchan Return a number of channels
ncycle Return a number of cycles
nif Return a number of IFs
npol Return a number of polarizations
nrow Return a number of rows
nscan Return a number of scans
opacity Apply an opacity correction
parallactify Set a flag to indicate the data should be treated as ”parallactified”
poltype Get a polarization type
poly_baseline Perform a baseline subtraction using polynomial function
recalc_azel Recalculate azimuth and elevation for each sky position
resample Perform a binning
rotate_linpolphaseRotate a phase of the complex polarization
rotate_xyphase Rotate a phase of the XY correlation
save Store the scantable on disk
scale Scale spectra by the given factor
set_dirframe Set the frame type of the direction on the sky
set_doppler Set definition of the Doppler correction
set_feedtype Set the feed type
set_fluxunit Set flux unit
set_freqframe Set the frame type of the spectral axis
set_instrument Set antenna name
set_restfreqs Set rest frequency
set_selection Select a subset of the data
set_sourcetype Set the types of source to be source or reference scan
set_spectrum Set spectrum for specified row
set_unit Set unit for spectral axis
shift_refpix Shift the reference pixel of the spectral coordinate
sinusoid_baselinePerform a baseline subtraction using sinusoidal function
smooth Smooth the spectra
stats Compute specified statistics of the spectra
stddev Compute standard deviation of the spectra
summary Print a summary of the contents of the scantable
swap_linears Swap the linear polarizations XX and YY

    sd.scantable.add - Function
    sd.scantable.auto_cspline_baseline - Function
    sd.scantable.auto_poly_baseline - Function
    sd.scantable.auto_quotient - Function
    sd.scantable.auto_sinusoid_baseline - Function
    sd.scantable.average_beam - Function
    sd.scantable.average_pol - Function
    sd.scantable.average_time - Function
    sd.scantable.bin - Function
    sd.scantable.chan2data - Function
    sd.scantable.clip - Function
    sd.scantable.convert_flux - Function
    sd.scantable.convert_pol - Function
    sd.scantable.copy - Function
    sd.scantable.create_mask - Function
    sd.scantable.cspline_baseline - Function
    sd.scantable.drop_scan - Function
    sd.scantable.fft - Function
    sd.scantable.flag - Function
    sd.scantable.flag_nans - Function
    sd.scantable.flag_row - Function
    sd.scantable.freq_align - Function
    sd.scantable.freq_switch - Function
    sd.scantable.gain_el - Function
    sd.scantable.get_abcissa - Function
    sd.scantable.get_antennaname - Function
    sd.scantable.get_azimuth - Function
    sd.scantable.get_column_names - Function
    sd.scantable.get_coordinate - Function
    sd.scantable.get_direction - Function
    sd.scantable.get_directionval - Function
    sd.scantable.get_elevation - Function
    sd.scantable.get_fit - Function
    sd.scantable.get_fluxunit - Function
    sd.scantable.get_inttime - Function
    sd.scantable.get_mask - Function
    sd.scantable.get_mask_indices - Function
    sd.scantable.get_masklist - Function
    sd.scantable.get_parangle - Function
    sd.scantable.get_restfreqs - Function
    sd.scantable.get_rms - Function
    sd.scantable.get_row - Function
    sd.scantable.get_row_selector - Function
    sd.scantable.get_scan - Function
    sd.scantable.get_selection - Function
    sd.scantable.get_sourcename - Function
    sd.scantable.get_spectrum - Function
    sd.scantable.get_time - Function
    sd.scantable.get_tsys - Function
    sd.scantable.get_unit - Function
    sd.scantable.get_weather - Function
    sd.scantable.getbeam - Function
    sd.scantable.getbeamnos - Function
    sd.scantable.getcycle - Function
    sd.scantable.getif - Function
    sd.scantable.getifnos - Function
    sd.scantable.getmolnos - Function
    sd.scantable.getpol - Function
    sd.scantable.getpolnos - Function
    sd.scantable.getscan - Function
    sd.scantable.getscannos - Function
    sd.scantable.history - Function
    sd.scantable.invert_phase - Function
    sd.scantable.lag_flag - Function
    sd.scantable.mx_quotient - Function
    sd.scantable.nbeam - Function
    sd.scantable.nchan - Function
    sd.scantable.ncycle - Function
    sd.scantable.nif - Function
    sd.scantable.npol - Function
    sd.scantable.nrow - Function
    sd.scantable.nscan - Function
    sd.scantable.opacity - Function
    sd.scantable.parallactify - Function
    sd.scantable.poltype - Function
    sd.scantable.poly_baseline - Function
    sd.scantable.recalc_azel - Function
    sd.scantable.resample - Function
    sd.scantable.rotate_linpolphase - Function
    sd.scantable.rotate_xyphase - Function
    sd.scantable.save - Function
    sd.scantable.scale - Function
    sd.scantable.set_dirframe - Function
    sd.scantable.set_doppler - Function
    sd.scantable.set_feedtype - Function
    sd.scantable.set_fluxunit - Function
    sd.scantable.set_freqframe - Function
    sd.scantable.set_instrument - Function
    sd.scantable.set_restfreqs - Function
    sd.scantable.set_selection - Function
    sd.scantable.set_sourcetype - Function
    sd.scantable.set_spectrum - Function
    sd.scantable.set_unit - Function
    sd.scantable.shift_refpix - Function
    sd.scantable.sinusoid_baseline - Function
    sd.scantable.smooth - Function
    sd.scantable.stats - Function
    sd.scantable.stddev - Function
    sd.scantable.summary - Function
    sd.scantable.swap_linears - Function


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