; CLBOX
;---------------------------------------------------------------
;! specifies subarrays of an image for Clean to search
;# ADVERB IMAGING
;-----------------------------------------------------------------------
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;-----------------------------------------------------------------------
CLBOX       LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
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CLBOX
Type: Adverb   (Real(4,50))
Use:  An array containing 50 sets of of four numbers that are
      normally used to specify areas within which model
      sources may be found (e.g. point sources found by Clean).
      The number of such areas is normally given by the value
      of the NBOXES adverb.

      All tasks that use the CLBOX adverb support the definition
      of rectangular areas in which the four numbers are the
      x and y pixel coordinates of the bottom-left corner
      followed by the x and y coordinates of the top-right
      corner in pixels.  IMAGR, SCMAP and SCIMG also support
      the definition of circular areas by setting: a circular
      area is specified by setting the first number to -1, the
      second to the radius of the circle on pixels and the third
      and fourth to the x and y pixel coordinates of the centre.
Null value:   0
      Null value assignment varies with the verb or task.
Tasks:
   APCLN.......Deconvolves images with CLEAN algorithm.
   BSCLN.......Hogbom Clean on beam-switched difference image.
   CCEDT.......Select CC components in BOXes and above mininum flux.
   CHKFC.......Makes images of Clean boxes from Boxfile.
   CXCLN.......Complex Hogbom CLEAN.
   FIXBX.......Converts a BOXFILE to another for input to IMAGR.
   GREYS.......Plots images as contours over multi-level grey.
   IMAGR.......Wide-field and/or wide-frequency Cleaning / imaging
               task.
   ISPEC.......Plots and prints spectrum of region of a cube.  The
               spectrum is found only inside or only outside the
               CLBOXS.
   QUFIX.......Determines Right minus Left phase difference, corrects
               cal files.
   RSPEC.......Plots and prints spectrum of rms of a cube.  The rms
               is found only inside or only outside the CLBOXs.
   SCIMG.......Full-featured imaging plus self-calibration loop with
               editing.
   SCMAP.......Imaging plus self-calibration loop with editing.
   SDCLN.......Deconvolves image by Clark and then "SDI" cleaning
               methods.
Verbs:
   DELBOX......Verb to delete boxes with TV cursor & graphics display.
   DRAWBOX.....Verb to draw Clean boxes on the display.
   REBOX.......Verb to reset boxes with TV cursor & graphics display.
   TVBOX.......Verb to set boxes with TV cursor & graphics display.
Procedures:
   BOX2CC......Converts CLBOX in pixels to CCBOX in arc seconds.
   CXIMAGR.....Grid UV data into a complex image, Fourier transform,
               Clean.
   LINIMAGE....Build image cube from multi-IF data set.
   MAPPR.......Simplified access to IMAGR.
   TKBOX.......Procedure to set a Clean box with the TK cursor.
   TKNBOXS.....Procedure to set Clean boxes 1 - n with the TK cursor.
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