C
C@cobsn.i
C
      Integer*4 Nzero
      COMMON / OBSRVN / Nzero
C  Mods:
C     98.07.29 - D. Gordon  Include file and comon block created. 
C
C       1. Nzero   -  Set equal to 1 or 2 if station 1 or 2 is at the geocenter.
C                     Otherwise zero.