How are ALMA data products packaged?
Posted by Anand Crossley, Last modified by Felix Stoehr on 11 March 2019 12:50 PM
For Cycles 5 and onwards, raw data and processed data are ingested into the archive as individual files. Upon retrieval - optionally - they are packaged together into tarfiles for better downloads. Data from earlier cycles are directly stored as tar files in the storage system.
A more detailed description of the data products can be found in the document ALMA QA2 Data Products that can be found on the Documents page in the Science Portal.
The raw data are written in ALMA Science Data Model (ASDM) format with file names
Processed data sets include:
The processed data file holding the FITS products have file names
<PROJECT CODE>_<OUS UID>_<X>_of_<Y>.tar
A CASA measurement set of calibrated visibilities can be created using the scripts contained in the processed data set by following the instructions outlined in this KB article: How do I obtain a file of calibrated visibilities ("measurement set") for ALMA data?
In Cycles 1-4 the processed data products are packaged (mostly) into the same
<PROJECT CODE>_<DATA DELIVERY DATE>_<X>_of_<Y>.tar
As a consequence of including the raw and calibrated measurement sets, these older tar files are much larger than the processed data files currently ingested. The raw ASDM was not included in these older files but can still be obtained by submitting a query to the ALMA Helpdesk.