SUBROUTINE  PLTRG (X1,X,X2,Y1,Y,Y2,N)

C     [RECTANGULAR GRAPH]
C     PLOT A GRAPH IN RECTANGULAR COORDINATES, BY CONNECTING SUCCESSIVE
C     DATA POINTS BY STRAIGHT LINES. THE POINTS DEFINING THE GRAPH ARE
C     TAKEN FROM TWO ARRAYS, ONE CONTAINING THE X-VALUES AND THE OTHER
C     CONTAINING THE Y-VALUES.  THE RESPECTIVE SCALES ARE INDICATED BY
C     THE VALUES TO BE ASSIGNED TO THE MARGINS OF THE GRAPH. ORDINARILY
C     THE MARGINS WOULD BE GIVEN ROUNDED VALUES SLIGHTLY LARGER THAN
C     THE EXTREME DATA VALUES.  HOWEVER, THE GRAPH MAY BE CENTERED IN
C     VARIOUS WAYS BY ASSIGNING ONE OR MORE MARGINS CONSIDERABLY LARGER
C     VALUES.  LIKEWISE EXCERPTS FROM THE GRAPH MAY BE CHOSEN BY GIVING
C     THE MARGINS LESSER VALUES THAN THE EXTREMES.
C     X1     X LOWER LIMIT
C     X(N)   ARRAY OF X VALUES
C     X2     X UPPER LIMIT
C     Y1     Y LOWER LIMIT
C     Y(N)   ARRAY OF Y VALUES
C     Y2     Y UPPER LIMIT
C     N      NUMBER OF POINTS
C     [12-OCT-74]

      DIMENSION   X(1),Y(1)
      DATA        HX,HY/4.50,3.25/

      EX(X)=(X-X1)*SCX-HX
      WY(Y)=(Y-Y1)*SCY-HY

      IF (N.LT.2) RETURN
      SCX=(2.0*HX)/(X2-X1)
      SCY=(2.0*HY)/(Y2-Y1)
      CALL PLTMS (EX(X(1)),WY(Y(1)),.FALSE.)
      DO 10 I=2,N
   10 CALL PLTMS (EX(X(I)),WY(Y(I)),.TRUE.)
      RETURN

      END