; UVWTFN
;---------------------------------------------------------------
;! Specify weighting function, Uniform or Natural
;# ADVERB UV IMAGING
;-----------------------------------------------------------------------
;;  Copyright (C) 1995
;;  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:
;;         Internet email: aipsmail@nrao.edu.
;;         Postal address: AIPS Project Office
;;                         National Radio Astronomy Observatory
;;                         520 Edgemont Road
;;                         Charlottesville, VA 22903-2475 USA
;-----------------------------------------------------------------------
;---------------------------------------------------------------
UVWTFN    LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
UVWTFN
Type:  Adverb (String*2)
Use:   Specify weighting function used to equalize coverage
       of measured points in UV plane and otherwise adjust the
       weights.  It is a two character code.  If the first is
       'N' then there is no correction to the data weights for
       the local density of samples or weights.  If it is 'C',
       then the weights are corrected for the local density of
       samples (simple counts).  Otherwise, the weights are
       corrected for the local density of data weights
       (so-called uniform weighting).  The second character
       causes the weights to be modified before the local
       density of weights is measured and aganin before they are
       used.  If the second character is the letter 'V', the
       fourth root of the weights is taken; if it is 'S' the
       square root of the weights is taken; and if it is the
       letter 'O' all weights are taken as 1.0.
Null Value:  '  '
       Null value means Uniform weighting with no conversion of
       weights.
----------------------------------------------------------------
