program main
  implicit none
  integer :: nx, ny, nz
  character(16) :: header(64)
  real,allocatable  :: dat(:,:,:)

  nx = 128
  ny = 256
  nz = 1

  allocate(dat(nx,ny,nz))

  open(11, file='file.gt', form='unformatted', status='old')
  read(11) header
  read(11) dat
  close(11)

end program main