Convert an Science Data Model observation into a CASA Measurement Set
Convert a Science Data Model (SDM) dataset into a CASA Measurement Set (MS).
Will place online flags and specified clip/shadow flags into FLAG_CMD table
and optionally apply to MS.
Warning: This version is under development and is geared to handling EVLA
specific flag and system files, and is otherwise identical to importasdm.
HISTORY: Task created v1.0 S.T. Myers 2010-03-11 (3.0.1)
Last updated v9.0 S.M. Castro 2012-03-13 (3.4) code+doc
Keyword arguments:
asdm -- Name of input SDM file (directory)
default: none;
Example: asdm='ExecBlock3'
vis -- Root ms or scantable name, note a .ms is NOT appended to name
default: none
ocorr_mode -- output data for correlation mode AUTO_ONLY
(ao) or CROSS_ONLY (co) or CROSS_AND_AUTO (ca)
default: co (for EVLA)
compression -- produces comrpressed columns in the resulting measurement set.
default: False
asis -- creates verbatim copies of the ASDM tables in
the output measurement set. The value given to
this option must be a list of table names separated
by space characters; the wildcard character '*' is
allowed in table names.
scans -- processes the scans requested in this parameter (default is
all scans). For simplest use provide a comma-separated list of
scan ranges, e.g. scans='1~3,5,10~20'.
default: '' = all scans
NOTE: A scan specification tecnically consists of an ExecBlock
index followed by the character ':' followed by a comma
separated list of scan indexes or scan index ranges. The EVLA
does not currently include more than one ExecBlock in a SDM
so this specification prefix is not needed.
By default all the scans are considered.
overwrite -- Over write an existing MS
verbose -- produce log output as asdm2MS is being run
EVLA-specific parameters:
-------------------------
online -- create flagging commands for online flags. The commands will be saved to the FLAG_CMD
sub-table of the MS. Optionally, it can also be saved to an ASCII file when savecmds is set
to True.
default: True
>>> online expandable parameters
tbuff -- (float) time padding buffer (in seconds)
default: 0.0
NOTE: this time is in seconds. You should currently
set the value of tbuff to be 1.5x the correlator
integration time if greater than 1 second. For
example, if the SDM has integrations of 3 seconds,
set tbuff=4.5. Likewise, set tbuff=15.0 for 10-sec
integrations.
flagzero -- create flags to clip out visibilities with zero values. The command will be saved to the FLAG_CMD
sub-table of the MS. Optionally, it can also be saved to an ASCII file when savecmds is set
to True.
default: True
>>> flagzero expandable parameter(s)
flagpol -- (boolean) also zero-clip on cross-hands (default=False)
shadow -- create flags for antennas that are shadowed. The command will be saved to the FLAG_CMD
sub-table of the MS. Optionally, it can also be saved to an ASCII file when savecmds is set
to True.
default: True
>>> shadow expandable parameter
tolerance -- Amount of shadowing allowed in meters.
default: 0.0
addantenna -- It can be either a file name with additional antenna names, positions
and diameters, or a Python dictionary with the same information.
You can use the flaghelper functions to create the dictionary from a file.
default: ''
To create a dictionary inside casapy.
> import flaghelper as fh
> antdic = fh.readAntennaList(antfile)
Where antfile is a text file in disk that contains information such as:
name=VLA01
diameter=25.0
position=[-1601144.96146691, -5041998.01971858, 3554864.76811967]
name=VLA02
diameter=25.0
position=[-1601105.7664601889, -5042022.3917835914, 3554847.245159178]
applyflags -- apply the online and specified flags to the MS
default: False
savecmds -- Save the flag commands to an ASCII file given by the parameter outfile. It will save the
flag commands from online, flagzero and/or shadow if they are set to True.
default: False
>>> savecmds expandable parameter
outfile -- Filename where to save the flag commands.
default: ' ' --> by default it will save on a filename composed from the MS name.
Example: vis='evla.ms', the outfile will be 'evla_cmd.txt'.
NOTE: The file is open to save in append mode.
flagbackup -- Backup original flags in >ms<.flagversions
default: True
Examples:
1) Produces MS CLowTest_000.ms with autocorrelations.
You will find the online, zero, and shadow flags in the FLAG_CMD table
for later application. Does not apply any flags.
importevla(asdm='CLowTest_000',ocorr_mode='ca')
2) Produces MS CLowTest_000.ms without autocorrelations.
importevla(asdm='CLowTest_000')
3) Will apply online flags and uses a more conservative 2sec buffer
before the start and after the end timeranges.
importevla(asdm='CLowTest_000',online=True,tbuff=2.0,applyflags=True)
4) This will create the FLAG_CMD sub-table using online flags only,
but will not apply them to the MS.
importevla(asdm='CLowTest_000',online=True,flagzero=False,shadow=False)
5) This will write the online flags to the FLAG_CMD table. It will also save commands
to clip zeros and to flag shadowed antennas to the table. The commands will be further
applied to the data and the APPLIED column of the FLAG_CMD will be updated to True.
importevla(asdm='CLowTest_000',online=True,flagzero=True,shadow=True,applyflags=True)
6) Import only scans 1, 2, 3, 5, 7, 9, save the online, shadow and clip commands to an ASCII file and
do not apply the flags. The commands will be saved to CLowTest_000_cmd.txt.
importevla(asdm='CLowTest_000',scans='1~3,5,7,9',online=True,flagzero=True,shadow=True,
applyflags=False, savecmds=True)
You can use either flagdata or flagcmd to apply the flags later with the following commands:
Apply all the flags in the file using flagdata
flagdata('CLowTest_000.ms', mode='list', inpfile='CLowTest_000_cmd.txt')
Select by reason on the file
flagdata('CLowTest_000.ms',mode='list', inpfile='CLowTest_000_cmd.txt',
reason=['ANTENNA_NOT_POINTING','CORRELATOR_DATA_INVALID'])
Apply all the flags in the file using flagcmd
flagcmd('CLowTest_000.ms',inpmode='list',inpfile='CLTest_000_cmd.txt',action='apply')
HISTORY: Task last updated v9.0 S.M. Castro 2012-03-8 (3.4.0)
Docs last updated v9.0 S.M. Castro 2012-03-13 (3.4.0)
1.8.0