sdsave

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8.2.1.14 sdsave

Keyword arguments:
infile -- name of input SD dataset
antenna -- antenna name or id (only effective for MS input).
getpt -- fill DIRECTION column properly, or reuse POINTING table
         in original MS (only effective for MS input)
         default: True
         options: True (fill DIRECTION column properly)
                  False (reuse POINTING table in original MS)
rowlist -- list of row numbers to process
        default: [] (use all rows)
        example: [0,2,4,6]
        For expert users only!
        this selection is applied first, and then followed by
        the selection with scans, fields, ifs, and polarizations.
scanlist -- list of 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
scanaverage --  average integrations within scans
        options: (bool) True,False
        default: False
        example: if True, average integrations before it is saved
timeaverage -- average times for multiple scan cycles
        options: (bool) True,False
        default: False
        >>>timeaverage expandable parameter
         tweight -- weighting for time average
                 options: ’none’
                          ’var’   (1/var(spec) weighted)
                          ’tsys’  (1/Tsys**2 weighted)
                          ’tint’  (integration time weighted)
                          ’tintsys’  (Tint/Tsys**2)
                          ’median’  ( median averaging)
                 default: ’none’

polaverage -- average polarizations
        options: (bool) True,False
        default: False
        >>>polaverage expandable parameter
         pweight -- weighting for polarization average
                 options: ’none’
                          ’var’  (1/var(spec) weighted)
                          ’tsys’ (1/Tsys**2 weighted)
outfile -- name of output dataset
        default: ’’
outform -- output data format
        default: ’ASAP’
        Options: ’ASAP’, ’MS2’, ’SDFITS’, ’ASCII’
overwrite -- overwrite the output file if already exists
        options: (bool) True,False
        default: False
        WARNING: if outform=’ASCII’, this parameter is ignored

DESCRIPTION:

Task sdsave writes the single dish data to a disk file in specified format (ASAP, MS2, SDFITS, ASCII). It is possible to save the subset of the data by selecting row numbers, scan numbers, IF ids and field names. The ASAP (scantable) format is recommended for further analysis using sd tool. For further imaging using imager, save the data to the Measurement Set (MS2).

Note that setting getpt=False needs a lot of attention. If you set getpt=False, the task retrieves pointing direction from MS’s FIELD table, which might not be correct for single dish observation, instead to check MS’s POINTING table, which is the default behavior of the task (getpt=True). To compensate this, absolute path to MS’s POINTING table is stored, and it will be used for POINTING table when the data is converted back to MS format. In general, getpt=False is faster especially for large data. However, MS created from Scantable cannot have correct POINTING table if original MS’s POINTING table doesn’t exist. Such situation will happen when original MS is removed or renamed, or imported Scantable is moved to other computer alone.

See the sdcal description for note on GBT raw SDFITS format data.

WARNING: The parameter rowlist enables you to make data selection based on row number in the Measurement Set or scantable for data saving. Note that data should be treated carefully when applying row based selection, since row numbers can be changed easily by sorting, prior selection, etc. Therefore, this parameter is expected to be used by expert users only .

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