;-------------------------------------------------------------
;+
; NAME:
;       LINFILL
; PURPOSE:
;       Fill gaps in array data using linear interpolation.
; CATEGORY:
; CALLING SEQUENCE:
;       LINFILL,A,I1,I2
; INPUTS:
;       A = array to operate on.                         in
;       I1 = index in A of last good value before gap.   in
;       I2 = index in A of first good value after gap.   in
; KEYWORD PARAMETERS:
; OUTPUTS:
;       A = updated array.                               out
; COMMON BLOCKS:
; NOTES:
; MODIFICATION HISTORY:
;       Ray Sterner,  6 Mar, 1985.
;       Johns Hopkins University Applied Physics Laboratory.
;
; Copyright (C) 1985, Johns Hopkins University/Applied Physics Laboratory
; This software may be used, copied, or redistributed as long as it is not
; sold and this copyright notice is reproduced on each copy made.  This
; routine is provided as is without any express or implied warranties
; whatsoever.  Other limitations apply as described in the file disclaimer.txt.
;-
;-------------------------------------------------------------
 
 
    PRO LINFILL,A,I1,I2, help=hlp
 
    if (n_params(0) lt 3) or keyword_set(hlp) then begin
      print,' Fill gaps in array data using linear interpolation.
      print,' LINFILL,A,I1,I2
      print,'   A = array to operate on.                         in'
      print,'   I1 = index in A of last good value before gap.   in'
      print,'   I2 = index in A of first good value after gap.   in'
      print,'   A = updated array.                               out'
      return
    endif
 
    V1 = A(I1)
    V2 = A(I2)
 
    SC = (V2-V1)/(I2-I1)
 
    FOR I = I1+1L, I2-1L DO A(I) = (I-I1)*SC + V1
 
    RETURN
 
    END