Program nvap_read_ds
c
c----------------------------------------------------------------------
c
c This routine will read in a NVAP (1/2 degree only) Data Source Bit (DS)
c file and convert it to a CCDA data file with 16 grids of 'data source'
c as shown below (tlabel(1-16).  The routine is written for an 
c example of the DS reading capability.
c
c written by Dave Randel STC/METSAT
c in February 2003
c
c----------------------------------------------------------------------
c
      character*50 flname, flout
	character*40 tlabel(16)
	integer*2 dsb(720,360),istat
c
c--------COMMON BLOCK WHICH HOLDS THE DATA AND HEADER INFORMATION---------
c
       real nvdata(720,360), headr(4), zindef
cmy fix
       integer*2 headi(11), igrd
cend fix
       character label*40
       common /nvapdata/ nvdata, headr, zindef, headi, label
c
c-------------------------------------------------------------------------
c
      tlabel(1)  = 'DSB SSM/I Leftovers'
      tlabel(2)  = 'DSB SSM/I Sat 1'
      tlabel(3)  = 'DSB SSM/I Sat 2'
      tlabel(4)  = 'DSB SSM/I Sat 3'
      tlabel(5)  = 'DSB Pathfinder Path A TOVS'
      tlabel(6)  = 'DSB ATOVS N15'
      tlabel(7)  = 'DSB ATOVS N16'
      tlabel(8)  = 'DSB SSM/T2 Sat 1'
      tlabel(9)  = 'DSB SSM/T2 Sat 2'
      tlabel(10) = 'DSB AMSUB N15'
      tlabel(11) = 'DSB AMSUB N16'
      tlabel(12) = 'DSB TMI  TRMM'
      tlabel(13) = 'TOPOGRAPHICALLY REMOVED'
      tlabel(14) = 'SPATIAL INTERPOLATED'
      tlabel(15) = 'TEMPORAL INTERPOLATED'
      tlabel(16) = 'MISSING'
	nbits = 16
c
c--set generic format statements
 1    format(a,$)
 2    format(a50)
 3    format(a)
c
c--get input/output filenames -------------------------
c
	write(6,1)' NVAP-NG Data Source Bitmap filename? : '
	read(5,2) flname
	write(6,1)'      Output CCDA formatted filename? : '
	read(5,2) flout
c
c--loop over fields in file and output a nvap grid file
c
      nout = 0
cmy fix
      do igrd = 1,1000
cend fix
        call nvap_read_dsb(flname, igrd, dsb, istat)
	  if(istat .ne. 0) then
	      write(6,*)'**ERROR** reading dsb field',ifld, istat
	      write(6,*)'        might just be end of file'
	      stop 100
	  endif
c
c-----------------------------------------------------------------------
c
c  BTEST used below is a non-standard function to test for bit condition
c  being "ON".  This test if bit 0 - 15 are on, and sets gridded value
c  to 100 if true.
c
c-----------------------------------------------------------------------
c
        do ibit = 1,nbits
          do iy = 1,360
	      do ix = 1,720
	        if(BTEST(dsb(ix,iy),ibit-1)) then
                   nvdata(ix,iy) = 100.0
	        else
	             nvdata(ix,iy) = zindef
	        endif
	      enddo
	    enddo
          nout = nout + 1
	    label = tlabel(ibit)
          call nvap_write(flout,nout,istat)
	    if(istat .ne. 0) then
	        write(6,*)'**ERROR** writing nvap field = ',nout
	        stop 200
	    endif
          do iy = 1,360          !clear out array
	      do ix = 1,720
	        nvdata(ix,iy) = zindef
	      enddo
	    enddo
	  enddo
        write(6,*)' finished writing 16 grids for field : ',igrd

	enddo
      write(6,*)' normal completion '
	stop
	end