Makemask

Help on makemask task:

Make a mask image from rectangular boxes

        The mask image must be consistent with a particular visibility file and source
        selection; hence the need to specify the imaging parameters and source
        selection.

        If the source image has already been made, then a mask image can be made by:

                 Load the image into the viewer
                 click on tools (top just left of center)
                 click on Region Manager
                 make  rectangular and/or polygon areas as needed
                 save as region file
                 This region file can substitute as a mask in most application.

        You can also use taskname='clean' with interactive = T to make a mask when the
        dirty image is produced.


        Keyword arguments:
        cleanbox -- Cleaning region:
                default: [] defaults to inner quarter of image
                Two specification types:
                Explicit pixel ranges
                   example: cleanbox=[[110,110,150,145],[180,70,190,80]]
                   cleans two regions defined by the pixel ranges
                Filename with pixel values with ascii format:
                   <fieldid blc-x blc-y trc-x trc-y> on each line
        ----------------------------------------------------------------
        vis -- Name of input visibility file
                default: none; example: vis='ngc5921.ms'
        imagename -- Name of output mask image
                default: none; example: imagename='ngc5921.mask'
        mode -- Type of selection
                default: 'mfs'; example: mode='channel';
                Options: 'mfs', channel'
        nchan -- Number of channels to select
                default: -1 (all); example: nchan=45
        start -- Start channel
                default=0; example: start=5
        width -- Channel width (value > 1 indicates channel averaging)
                default=1; example: width=5
        step -- Step in channel number
                default=1; example: step=2
        imsize -- Image size in spatial pixels (x,y)
                default = [256,256]; example: imsize=[512,512]
        cell -- Cell size in arcseconds (x,y)
                default=[0,0] = none; example: cell=[0.5,0.5]
        phasecenter -- direction measure  or fieldid for the mosaic center
                default: '' (imply field=0 as center); example: phasecenter=6
                or phasecenter='J2000 19h30m00 -40d00m00'
        stokes -- Stokes parameters to image
                default='I'; example: stokes='IQUV';
                Options: 'I','IV','IQU','IQUV'
        field -- Select field using field id(s) or field name(s).
                  [run listobs to obtain the list id's or names]
                default: ''=all fields
                If field string is a non-negative integer, it is assumed a field index
                  otherwise, it is assumed a field name
                field='0~2'; field ids 0,1,2
                field='0,4,5~7'; field ids 0,4,5,6,7
                field='3C286,3C295'; field named 3C286 adn 3C295
                field = '3,4C*'; field id 3, all names starting with 4C
        spw -- Select spectral window/channels
                default: ''=all spectral windows and channels
                spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
                spw='<2';  spectral windows less than 2 (i.e. 0,1)
                spw='0:5~61'; spw 0, channels 5 to 61
                spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45.
                spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
                spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60
                spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10,
                   spw 1, channels 20-30, and spw 2, channels, 1,2 and 3