4    'nports' = number of boundary port sections
   2    'kdport' = port orientation (1=N, 2=S, 3=E, 4=W)
  68    'ifport' = first i-index
 372    'ilport' = last  i-index (=ifport for east/west port)
   2    'jfport' = first j-index
   2    'jlport' = last  j-index (=jfport for north/south port)
   2    'kdport' = port orientation (1=N, 2=S, 3=E, 4=W)
 377    'ifport' = first i-index
 652    'ilport' = last  i-index (=ifport for east/west port)
   2    'jfport' = first j-index
   2    'jlport' = last  j-index (=jfport for north/south port)
   2    'kdport' = port orientation (1=N, 2=S, 3=E, 4=W)
 686    'ifport' = first i-index
 711    'ilport' = last  i-index (=ifport for east/west port)
   2    'jfport' = first j-index
   2    'jlport' = last  j-index (=jfport for north/south port)
   3    'kdport' = port orientation (1=N, 2=S, 3=E, 4=W)
 712    'ifport' = first i-index
 712    'ilport' = last  i-index (=ifport for east/west port)
   2    'jfport' = first j-index
  15    'jlport' = last  j-index (=jfport for north/south port)