Region Selection (box)

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6.1.1 Region Selection (box)

Direction (eg RA, Dec) areal selection in the image analysis tasks is controlled by the box parameter or through the region parameter (§ 6.1.5). Note that one should either specify a region (recommended) or any of box/chans/stokes. Specifying both at the same time is not unique anymore and can lead to unwanted selections. In the future we may remove the box/chans/stokes selection (for CASA 3.3 we keep both selection methods for backward compatibility).

The box parameter selects spatial rectangular areas (this parameter will be removed for CASA 3.4 and higher):

box        =      ’’   #  Select one or more box regions

#          string containing blcx,blcy,trcx,trcy

#          A box selection in the directional portion of an image.
#          The directional portion of an image are the axes for right
#          ascension and declination, for example.  Boxes are specified
#          by there bottom-left corner (blc) and top-right corner (trc)
#          as follows: blcx, blcy, trcx, trcy;
#          ONLY pixel values acceptable at this time.
#          Default: none (all);
#          Example: box=’0,0,50,50’

To get help on box, see the in-line help

help(par.box)

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