program mapasciitoascii
c     convert an ascii map file to an ascii map file but delete any
c     longitudes outside the goes-17 projection range:
c     namely, anything 90 degrees of longitude from the center longitude of 137W
      implicit none
c
      integer numvals, numpts, maxnumpts
      real xlatmin,xlatmax,xlonmin,xlonmax
      integer ia, i, iunit, ounit
      character*256 fname,fname2
      character fullpath*256
      integer, parameter :: maxpts = 59617
      real xlatmap(maxpts),xlonmap(maxpts)

      real, parameter :: g17lon = -137.
      real right, left, negleft, posright, a, b
      logical iuse

      left = g17lon - 90. + 360.
      right = g17lon + 90.
      negleft = -180.
      posright = 180.
      maxnumpts = 0
      call getarg(1,fname)
      i = index(fname,'.ascii')
      if (i.lt.0) then
         print *,'ERROR: looking for a filename that ends in .ascii'
         call exit(1)
      endif
      fname2 = fname(1:i)//"g17"
      iunit = 11
      ounit = 12
      open (unit=ounit,file=fname2,form='formatted',
     &     status='unknown',err=35)
      open (unit=iunit,file=fname,form='formatted',
     &      status='old',err=33)
 10   continue
      read(iunit,*,end=1000) numvals,xlatmin,xlatmax,
     &     xlonmax,xlonmin,xlatmap(1),xlonmap(1)
      numpts=numvals/2
      maxnumpts = max(numpts,maxnumpts)
      if (numpts.gt.maxpts) then
         print '("numvals = ",i8," numpts > maxpts ",2(i8,1x))'
     $        ,numvals,numpts,maxpts
      endif
      read(iunit,'(8F9.3)')(xlatmap(i),xlonmap(i),i=2,numpts)
      iuse = .false.
      if (xlonmin.gt.xlonmax) then
         a = xlonmin
         b = xlonmax
         xlonmax = a
         xlonmin = b
      endif
      if (xlonmin.lt.0.) then
         if (xlonmin.ge.negleft  .and. xlonmax.le.right) then
            iuse = .true.
         endif
      else
         if (xlonmin.ge.left .and. xlonmax.le.posright) then
            iuse = .true.
         endif
      endif

      if (iuse) then
         write(ounit,'(i4,14x,6F9.3)')
     $        numvals,xlatmin,xlatmax,xlonmin,xlonmax
     $        ,xlatmap(1),xlonmap(1)
         write(ounit,'(8F9.3)')(xlatmap(i),xlonmap(i),i=2,numpts)
      endif
      goto 10
1000  continue
      close (iunit)
      print *,'maxnumvals = ',2*maxnumpts
      print *,'maxnumpts = ',maxnumpts
      close (ounit)
c
      stop
c
 33   continue
      write(*,*)'Could not open ',trim(fname),' for reading.'
      call exit(1)
 35   continue
      write(*,*)'Could not open file ',trim(fname2),' for writing.'
      call exit(1)
c
      end