SUBROUTINE PCON
C
C Copy a global context table from a text file to the header
C of a context image
C
C Richard Hook, March 1999
C
      IMPLICIT NONE

      INTEGER MAXEN,MAXIM,NEN,ID,MAXHCN,I1,I2
      PARAMETER (MAXEN=20000,MAXIM=1000,MAXHCN=20)
      INTEGER A(MAXIM,MAXEN),ISTAT

      CHARACTER*80 CONTAB,IMAGE,CONNEW

C Get the name of the context table
      CALL UCLGST('contab',CONTAB,ISTAT)

C Get the name of the image to which the context is to be written
      CALL UCLGST('image',IMAGE,ISTAT)

C Also prepare a name for a possible context table in the header
      CALL LENSTR(IMAGE,I1,I2)
      CONNEW=IMAGE(I1:I2)//'.CON'

C Open the image with update access
      CALL UIMOPN(IMAGE,2,ID,ISTAT)
      IF(ISTAT.NE.0) THEN
         CALL UMSPUT('! Unable to open image file',1,0,ISTAT)
         GO TO 99
      ENDIF

C Read the context table from the text file
      CALL GTGLCO(CONTAB,A,MAXIM,MAXEN,NEN,ISTAT)
      IF(ISTAT.NE.0) THEN
         CALL UMSPUT('! Unable to read context table file',
     :               1,0,ISTAT)
         GO TO 88
      ENDIF

C Write the context to the image
      CALL PTCOIN(ID,CONNEW,MAXHCN,A,MAXIM,MAXEN,NEN,ISTAT)
      IF(ISTAT.NE.0) THEN
         CALL UMSPUT('! Unable to write context to header',
     :               1,0,ISTAT)
      ENDIF

 88   CONTINUE

C Close the image
      CALL UIMCLO(ID,ISTAT)

 99   CONTINUE
      RETURN
      END