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NRAO Home > CASA > CASA Task Reference Manual |
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0.1.143 visstat2
Requires:
Synopsis
Displays statistical information from a Measurement Set, or from a Multi-MS
Arguments
Outputs |
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xstat |
| Statistical information for the selected measurement set | |
| allowed: | any |
|
| Default: | variant | |
Inputs |
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vis |
| Name of Measurement Set or Multi-MS | |
| allowed: | string |
|
| Default: |
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axis |
| Which values to use
| |
| allowed: | string |
|
| Default: | amplitude |
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datacolumn |
| Which data column to use (data, corrected, model,
float_data)
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| allowed: | string |
|
| Default: | data | |
useflags |
| Take flagging into account?
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| allowed: | bool | |
| Default: | True |
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spw |
| spectral-window/frequency/channel
| |
| allowed: | string |
|
| Default: |
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field |
| Field names or field index numbers: ”==>all,
field=’0~2,3C286’
| |
| allowed: | string |
|
| Default: |
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selectdata |
| More data selection parameters (antenna, timerange etc)
| |
| allowed: | bool | |
| Default: | True |
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antenna |
| antenna/baselines: ”==>all, antenna = ’3,VA04’
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| allowed: | string |
|
| Default: |
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uvrange |
| uv range: ”==>all; uvrange = ’0~100klambda’, default
units=meters | |
| allowed: | string |
|
| Default: |
| |
timerange |
| time range: ”==>all, timerange=’09:14:0~09:54:0’
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| allowed: | string |
|
| Default: |
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correlation |
| Select data based on correlation
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| allowed: | string |
|
| Default: |
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scan |
| scan numbers: ”==>all
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| allowed: | string |
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| Default: |
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array |
| (sub)array numbers: ”==>all
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| allowed: | string |
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| Default: |
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observation |
| observation ID number(s): ” = all
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| allowed: | any |
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| Default: | variant
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timeaverage |
| Average data in time.
| |
| allowed: | bool |
|
| Default: | False |
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timebin |
| Bin width for time averaging.
| |
| allowed: | string |
|
| Default: | 0s |
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timespan |
| Span the timebin across scan, state or both.
| |
| allowed: | any |
|
| Default: | variant
|
|
maxuvwdistance |
| Maximum separation of start-to-end baselines that can
be included in an average. (meters)
| |
| allowed: | double |
|
| Default: | 0.0 |
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disableparallel |
| Hidden parameter for internal use only. Do not change
it!
| |
| allowed: | bool |
|
| Default: | False |
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ddistart |
| Hidden parameter for internal use only. Do not change
it!
| |
| allowed: | int |
|
| Default: | -1 |
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taql |
| Table query for nested selections
| |
| allowed: | string |
|
| Default: |
|
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monolithic_processing |
| Hidden parameter for internal use only. Do not change
it!
| |
| allowed: | bool |
|
| Default: | False |
|
intent |
| Select data by scan intent.
| |
| allowed: | any |
|
| Default: | variant
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reportingaxes |
| Which reporting axis to use (ddid, field, integration)
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| allowed: | string |
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| Default: | ddid |
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void
Example
This task returns statistical information about data in a Measurement
Set or Multi-MS.
The following values are computed: mean value, sum of values, sum of
squared values, median, median absolute deviation, first and third
quartiles, minimum, maximum, variance, standard deviation, and root mean
square.
The following axes are supported: uvw, flag, weight, sigma, antenna1,
antenna2, feed1, feed2, field_id, array_id, data_desc_id, flag_row,
interval, scan, scan_number, time, weight_spectrum, amp, amplitude,
phase, real, imag, imaginary, and uvrange.
Optionally, the statistical information can be computed based only
on a given subset of the measurement set.
Note: If the MS consists of inhomogeneous data, for example several
spectral windows each having a different number of channels, it may be
necessary to use selection parameters to select a homogeneous subset of
the MS, e.g. spw=’2’.
Keyword arguments:
vis --- Name of input Measurement Set or Multi-MS
default: ’’, example: vis=’my.ms’
axis -- Which data to analyze.
default: ’amplitude’
axis=’phase’
axis=’imag’
axis=’scan_number’
axis=’flag’
The phase of a complex number is in radians in the range [-pi; pi[.
datacolumn -- Which data column to use for complex data.
default: ’data’
datacolumn=’data’
datacolumn=’corrected’
datacolumn=’model’
datacolumn=’float_data’
useflags -- Take MS flags into account?
default: True
useflag=False
useflag=True
If useflags=False, flagged values are included in the statistics.
If useflags=True, any flagged values are not used in the statistics.
spw -- Select data based on spectral window and channels
default: ’’ (all); example: spw=’1’
spw=’<2’ #spectral windows less than 2
spw=’>1’ #spectral windows greater than 1
spw=’0:0~10’ # first 10 channels from spw 0
spw=’0:0~5;56~60’ # multiple separated channel chunks.
field -- Select data based on field id(s) or name(s)
default: ’’ (all); example: field=’1’
field=’0~2’ # field ids inclusive from 0 to 2
field=’3C*’ # all field names starting with 3C
selectdata -- Other data selection parameters
default: True
antenna -- Select data based on baseline
default: ’’ (all); example: antenna=’5&6’ baseline 5-6
antenna=’5&6;7&8’ #baseline 5-6 and 7-8
antenna=’5’ # all baselines with antenna 5
antenna=’5,6’ # all baselines with antennas 5 and 6
correlation -- Correlation types
default: ’’ (all);
example: correlation=’RR LL’
uvrange -- Select data within uvrange (default units meters)
default: ’’ (all); example:
uvrange=’0~1000klambda’; uvrange from 0-1000 kilo-lambda
uvrange=’>4klambda’;uvranges greater than 4 kilo-lambda
uvrange=’0~1000km’; uvrange in kilometers
timerange -- Select data based on time range:
default = ’’ (all); example,
timerange = ’YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’
Note: YYYY/MM/DD can be dropped as needed:
timerange=’09:14:0~09:54:0’ # this time range
timerange=’09:44:00’ # data within one integration of time
timerange=’>10:24:00’ # data after this time
timerange=’09:44:00+00:13:00’ #data 13 minutes after time
scan -- Select data based on scan number
default: ’’ (all); example: scan=’>3’
array -- Selection based on the antenna array
observation -- Selection by observation ID(s).
default: ’’ (all); example: observation=’1~3’
--- Time averaging parameters ---
timeaverage -- Average data in time. Flagged data will be included in the average
calculation, unless the parameter keepflags is set to False. In this
case only partially flagged rows will be used in the average.
WEIGHT_SPECTRUM/SIGMA_SPECTRUM will be used (if present) in
addition to the flags to compute a weighted average. The calculation is done
in the same way as for the channel average case but across the time axis.
Otherwise (if WEIGHT_SPECTRUM/SIGMA_SPECTRUM are not present)
mstransform will use WEIGH/SIGMA instead, as in split.
default: False
timebin -- Bin width for time averaging.
default: ’0s’
timespan -- Let the timebin span across scan, state or both.
State is equivalent to sub-scans. One scan may have several
state ids. For ALMA MSs, the sub-scans are limited to about
30s duration each. In these cases, the task will automatically
add state to the timespan parameter. To see the number of states
in an MS, use the msmd tool. See help msmd.
default: ’’ (separate time bins by both of the above)
options: ’scan’, ’state’, ’state,scan’
examples:
timespan = ’scan’; can be useful when the scan number
goes up with each integration as in many WSRT MSs.
timespan = [’scan’, ’state’]: disregard scan and state
numbers when time averaging.
timespan = ’state,scan’; same as above.
maxuvwdistance -- Provide a maximum separation of start-to-end baselines
that can be included in an average. (int)
default: 0.0 (given in meters)
More information about CASA may be found at the
CASA web page
Copyright © 2016 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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