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− | == Help on makemask task: ==
| + | {{makemask}} |
− | <pre>
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− | Make a mask image from rectangular boxes
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− | The mask image must be consistent with a particular visibility file and source
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− | selection; hence the need to specify the imaging parameters and source
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− | selection.
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− | If the source image has already been made, then a mask image can be made by:
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− | Load the image into the viewer
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− | click on tools (top just left of center)
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− | click on Region Manager
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− | make rectangular and/or polygon areas as needed
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− | save as region file
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− | This region file can substitute as a mask in most application.
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− | You can also use taskname='clean' with interactive = T to make a mask when the
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− | dirty image is produced.
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− | Keyword arguments:
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− | cleanbox -- Cleaning region:
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− | default: [] defaults to inner quarter of image
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− | Two specification types:
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− | Explicit pixel ranges
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− | example: cleanbox=[[110,110,150,145],[180,70,190,80]]
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− | cleans two regions defined by the pixel ranges
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− | Filename with pixel values with ascii format:
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− | <fieldid blc-x blc-y trc-x trc-y> on each line
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− | ----------------------------------------------------------------
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− | vis -- Name of input visibility file
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− | default: none; example: vis='ngc5921.ms'
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− | imagename -- Name of output mask image
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− | default: none; example: imagename='ngc5921.mask'
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− | mode -- Type of selection
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− | default: 'mfs'; example: mode='channel';
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− | Options: 'mfs', channel'
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− | nchan -- Number of channels to select
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− | default: -1 (all); example: nchan=45
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− | start -- Start channel
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− | default=0; example: start=5
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− | width -- Channel width (value > 1 indicates channel averaging)
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− | default=1; example: width=5
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− | step -- Step in channel number
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− | default=1; example: step=2
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− | imsize -- Image size in spatial pixels (x,y)
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− | default = [256,256]; example: imsize=[512,512]
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− | cell -- Cell size in arcseconds (x,y)
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− | default=[0,0] = none; example: cell=[0.5,0.5]
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− | phasecenter -- direction measure or fieldid for the mosaic center
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− | default: '' (imply field=0 as center); example: phasecenter=6
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− | or phasecenter='J2000 19h30m00 -40d00m00'
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− | stokes -- Stokes parameters to image
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− | default='I'; example: stokes='IQUV';
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− | Options: 'I','IV','IQU','IQUV'
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− | field -- Select field using field id(s) or field name(s).
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− | [run listobs to obtain the list id's or names]
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− | default: ''=all fields
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− | If field string is a non-negative integer, it is assumed a field index
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− | otherwise, it is assumed a field name
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− | field='0~2'; field ids 0,1,2
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− | field='0,4,5~7'; field ids 0,4,5,6,7
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− | field='3C286,3C295'; field named 3C286 adn 3C295
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− | field = '3,4C*'; field id 3, all names starting with 4C
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− | spw -- Select spectral window/channels
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− | default: ''=all spectral windows and channels
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− | spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
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− | spw='<2'; spectral windows less than 2 (i.e. 0,1)
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− | spw='0:5~61'; spw 0, channels 5 to 61
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− | spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45.
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− | spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
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− | spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60
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− | spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10,
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− | spw 1, channels 20-30, and spw 2, channels, 1,2 and 3
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− | </pre>
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