; DOHIST
;---------------------------------------------------------------
;! selects a histogram display or controls writing of history file
;# ADVERB PLOT CATALOG
;-----------------------------------------------------------------------
;;  Copyright (C) 1995, 2020
;;  Associated Universities, Inc. Washington DC, USA.
;;
;;  This program is free software; you can redistribute it and/or
;;  modify it under the terms of the GNU General Public License as
;;  published by the Free Software Foundation; either version 2 of
;;  the License, or (at your option) any later version.
;;
;;  This program is distributed in the hope that it will be useful,
;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;  GNU General Public License for more details.
;;
;;  You should have received a copy of the GNU General Public
;;  License along with this program; if not, write to the Free
;;  Software Foundation, Inc., 675 Massachusetts Ave, Cambridge,
;;  MA 02139, USA.
;;
;;  Correspondence concerning AIPS should be addressed as follows:
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;;         Postal address: AIPS Project Office
;;                         National Radio Astronomy Observatory
;;                         520 Edgemont Road
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;-----------------------------------------------------------------------
;---------------------------------------------------------------
DOHIST    LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
DOHIST
Type: Adverb  (Logical,  > 0  =>  true)
Use:  True (1) means create a histogram plot file.
      False (-1) means do not create a histogram plot file.
Null value:  false (-1).
Verbs:
   HINOTE........Adds user-generated lines to the history extension file.
                 DOHIST true menas pre-pend HINOTE to history line.
   PUTTHEAD......Inserts a given value into a table keyword/value pair.
                 DOHIST can suppress writing the function to history,
   PUTVALUE......Verb to store a pixel value at specified position.
                 DOHIST can suppress writing the function to history,
   TABPUT........Replaces table entry for specified row, column and
                 subscript.  DOHIST can suppress writing the function to
                 history,
Procedures:
   DOFARS........Procedure to aid in Faraday rotation synthesis using the
                 FARS task.  DOHIST controls how much history is copied.
Tasks:
   AFARS.........Is used after FARS to determine Position and Value of the
                 maximum.  DOHIST controls how much history is copied.
   ATMCA.........Determines delay/phase gradient from calibrator
                 observations.  DOHIST true puts results in history.
   BPEDT.........Interactive TV task to edit uv data based on BP tables.
                 DOHIST true requests flags to be listed in history.
   CALIB.........Determines antenna calibration: complex gain.  DOHIST
                 true requests input file history always to be updated.
   COMB..........Combines two images by a variety of mathematical methods.
                 DOHIST controls how much history is copied.
   DELZN.........Determines residual atmosphere depth at zenith and clock
                 errors.  DOHIST true puts results in history.
   EDITA.........Interactive TV task to edit uv data based on TY/SY/SN/CL
                 tables.  DOHIST true requests flags to be listed in
                 history.
   EDITR.........Interactive baseline-oriented visibility editor using the
                 TV.  DOHIST true requests flags to be listed in history.
   ELINT.........Determines and removes gain dependence on elevation.
                 DOHIST true puts results in history.
   FARS..........Faraday rotation synthesis based on the brightness vs
                 wavelength.  DOHIST controls how much history is copied.
   FTFLG.........Interactive flagging of UV data in channel-time using the
                 TV.  DOHIST true requests flags to be listed in history.
   HISEQ.........Task to translate image by histogram equalization.
                 DOHIST true causes intensities to be saved in history.
   IBLED.........Interactive BaseLine based visibility EDitor.
                 DOHIST true requests flags to be listed in history.
   IMEAN.........Displays the mean & extrema and plots histogram of an
                 image.  DOHIST requests a plot of the histogram.
   PCEDT.........Interactive TV task to edit pulse-cal (PC) tables.
                 DOHIST true requests flags to be listed in history.
   PCFLG.........Interactive flagging of Pulse-cal data in channel-TB
                 using the TV.  DOHIST true requests flags to be listed
                 in history.
   PDEDT.........Interactive TV task to edit polarization D-term (PD)
                 tables.  DOHIST true requests flags to be listed in
                 history.
   SERCH.........Finds line signals in transposed data cube.  DOHIST
                 controls the display of the histogram.
   SPFLG.........Interactive flagging of UV data in channel-TB using the
                 TV.  DOHIST true requests flags to be listed in history.
   SPMOD.........Modify UV database by adding a model with spectral lines.
                 DOHIST true lists source in history.
   TAPLT.........Plots data from a Table extension file.  DOHIST true
                 makes plopt into a histogram.
   TVFLG.........Interactive flagging of UV data using the TV.  DOHIST
                 true requests flags to be listed in history.
   UVFLG.........Flags UV-data.  DOHIST true requests flags to be listed
                 in history.
   UVMOD.........Modify UV database by adding a model incl spectral index.
                 DOHIST true lists all components in history.
----------------------------------------------------------------
