Scantable Manipulation

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8.3.3 Scantable Manipulation

Within ASAP, data is stored in a scantable, which holds all of the observational information and provides functionality to manipulate the data and information. The building block of a scantable is an integration which is a single row of a scantable. Each row contains just one spectrum for each beam, IF and polarization.

Once you have a scantable in ASAP, you can select a subset of the data based on scan numbers, sources, or types of scan; note that each of these selections returns a new ’scantable’ with all of the underlying functionality:

  CASA <5>: scan27=scans.get_scan(27)                 # Get the 27th scan
  CASA <6>: scans20to24=scans.get_scan(range(20,25))  # Get scans 20 - 24
  CASA <7>: scans_on=scans.get_scan(’*_ps’)           # Get ps scans on source
  CASA <8>: scansOrion=scans.get_scan(’Ori*’)         # Get all Orion scans

To copy a scantable, do:

CASA <15>: ss=scans.copy()

   8.3.3.1 Data Selection
   8.3.3.2 State Information
   8.3.3.3 Masks
   8.3.3.4 Scantable Management
   8.3.3.5 Scantable Mathematics
   8.3.3.6 Scantable Save and Export

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