<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" ?>
<casaxml xmlns="http://casa.nrao.edu/schema/psetTypes.html"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://casa.nrao.edu/schema/casa.xsd
file:///opt/casa/code/xmlcasa/xml/casa.xsd">
<task type="function" name="vishead" category="information, manipulation">
<shortdescription>List, summary, get, and put metadata in a measurement set</shortdescription>
<description>
This task allows the user to manipulate some meta-data keywords in a
measurement set. The mode='list' shows those keywords that are
presently implemented, with their values. The contents associated
with the keywords can be obtained (get) and changed (put).
The modes that are available are:
list --- List all keywords that are recognized, and list the
value(s) for each. Only these keywords can be obtained
(get) or changed (put)
summary --- Equivalent to running taskname='listobs'; verbose=F
get --- Get the specified keyword value(s) from the ms
put --- Put the specified keyword value(s) into the ms
Keywords currently implemented are:
cal_grp
field Field names
fld_code Field Observing codes
freq_group_name
log
observer Observer name
project Project name
ptcs Phase tracking centers for each field
release_date
schedule
schedule_type
spw_name Spectral parameters?
source_name Source Names (=Field Names?)
telescope Telescope Name
Note that the default list of keywords is a subset of the former list. To get
all the keywords set listitemts=[]. See task parameter listitems for more details.
</description>
<input>
<param type="string" name="vis" kind="ms" mustexist="true">
<description>Name of input visibility file</description>
<value></value>
<example>vis='ngc5921.ms'</example>
</param>
<param type="string" name="mode">
<description>Mode of operation for vishead</description>
<allowed kind="enum">
<value>list</value>
<value>summary</value>
<value>get</value>
<value>put</value>
<value></value>
</allowed>
<value>summary</value>
<example>
To list the available keywords in a MeasurementSet:
vishead(vis='measurementset.ms',mode='list')
To get a field name (string),
hdvalue=vishead(vis = '3C84C.ms', mode = 'get', hdkey = 'field', hdindex = '2');
print(hdvalue[0]) -> the name for field='2'
To get an phase center (number)
hdvalue = vishead(vis = '3C84C.ms', mode = 'get', hdkey = 'ptcs', hdindex = '1');
hdvalue[0][0] gives the ra, hdvalue[0][1] gives the dec in field '1'
To change a string,
vishead(vis = '3C84C.ms', mode = 'put', hdkey = 'field', hdindex = '2', hdvalue = 'junk')
field='2' is renamed 'junk'
</example>
</param>