2 Visibility Data Import, Export, and Selection

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Chapter 2
Visibility Data Import, Export, and Selection

To use CASA to process your data, you first will need to get it into a form that is understood by the package. These are “measurement sets” for synthesis (and single dish) data, and “image tables” for images.

There are a number of tasks used to fill telescope-specific data, to import/export standard formats, to list data contents, and to concatenate multiple datasets. These are:

asdmsummary — list the contents of a archive file in ASDM format (§ 2.2.1)
importasdm — import of ALMA data in ASDM format (§ 2.2.1)
importevla — import of EVLA/JVLA data and flags in ASDM format (§ 2.2.2)
importuvfits — import visibility data in UVFITS format (§ 2.2.4.1)
importfitsidi — import visibility data in the FITS-IDI format (§ 2.2.4.2)
importvla — import data from VLA that is in export format (§ 2.2.3)
exportuvfits — export a CASA MS in UVFITS format (§ 2.2.4.3)
listobs — summarize the contents of a MS (§ 2.2.6)
listvis — list the data in a MS (§ 2.2.7)
vishead — list and change the metadata contents of a MS (§ 2.2.8)
visstat — statistics on data in a MS (§ 2.2.9)
concat — concatenate two or more MS into a new MS (§ 2.2.10)

In CASA, there is a standard syntax for selection of data that is employed by multiple tasks. This is described in § 2.3.

There are also tasks for the import and export of image data using FITS:

listfits — show the header content of any FITS file (§ 2.1)
importfits — import a FITS image into a CASA image format table (§ 6.16)
exportfits — export a CASA image table as FITS (§ 6.16)

2.1 CASA Measurement Sets
  2.1.1 Under the Hood: Structure of the Measurement Set
2.2 Data Import and Export
  2.2.1 ALMA: Filling of Science Data Model (ASDM) data
  2.2.2 EVLA/JVLA: Filling of Science Data Model (ASDM) data
  2.2.3 VLA: Filling data from archive format (importvla)
  2.2.4 UVFITS Import and Export
  2.2.5 Handling Measurement Set metadata and data
  2.2.6 Summarizing your MS (listobs)
  2.2.7 Listing MS data (listvis)
  2.2.8 Listing and manipulating MS metadata (vishead)
  2.2.9 MS statistics (visstat)
  2.2.10 Concatenating multiple datasets (concat)
2.3 Data Selection
  2.3.1 General selection syntax
  2.3.2 The field Parameter
  2.3.3 The spw Parameter
  2.3.4 The selectdata Parameters

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Chapter 2Visibility Data Import, Export, and Selection

Chapter 2
Visibility Data Import, Export, and Selection