!==Example of Fortran writing GNUPLOT command and data file.
!  When done invoke GNUPLOT and issue: load "sample.gnu"
!  and it will plot the data in arrays X and Y.
       CHARACTER(Len=60) :: FIDMAP,FIDGNU, TITLE
       REAL :: X(100),Y(100)
       INTEGER :: I,N
       N=50
       TITLE='Example of GNUPLOT data and command file generation.'
       FIDMAP='SAMPLE.MAP'
       FIDGNU='SAMPLE.GNU'
       OPEN(70,FILE=FIDMAP)
       OPEN(80,FILE=FIDGNU)

!--Sample X,Y array. Alternatively one could read in Map coordinates.
       DO I=1,N
         X(I)=I
         Y(I)=(X(I)+0.5)**2
       END DO

!--Write the X,Y array as coordinates to be plotted.
       DO I=1,N
         WRITE(70,30) X(I),Y(I)
30       FORMAT(2F10.3)
       END DO

!--Write the GnuPlot command file.
       WRITE(80,15) TRIM(TITLE)
15     FORMAT('set title "',A,'"')
       WRITE(80,16)
16     FORMAT('set nokey')
       WRITE(80,17) TRIM(FIDMAP)
17     FORMAT('plot "',A,'" with lines')

!--Wrap up
       CLOSE(70)
       CLOSE(80)
       WRITE(*,*) 'Data to be plotted: ',FIDMAP
       WRITE(*,*) 'Gnuplot file to Open or Load: ',FIDGNU
       STOP
       END