SUBROUTINE  PLTRV (Z1,ZE,Z2,NX,MX,NY,TH)

C     [ROTATED VIEW]
C     PROGRAM TO PRODUCE A PERSPECTIVE DRAWING OF A SINGLE VALUED
C     FUNCTION DEFINED IN CARTESIAN COORDINATES, EXHIBITING ARCS
C     ON THE SURFACE PARALLEL TO THE COORDINATE AXES. FOR GREATER
C     VARIETY IN PRESENTATION, THE ENTIRE FIGURE MAY BE ROTATED
C     THROUGH AN ANGLE, WHICH SHOULD BE SPECIFIED IN DEGREES.
C     ZE     ARRAY OF FUNCTION VALUES
C     Z1,Z2  RANGE OF FUNCTION VALUES
C     NX     ACTUAL  LENGTH OF COLUMNS
C     MX     MAXIMUM LENGTH OF COLUMNS
C     NY     ACTUAL  LENGTH OF ROWS
C     TH     ANGLE OF ROTATION (-90.0.LT.TH.LT.90.0) IN DEGREES
C     [22-NOV-74]

      EXTERNAL    PLTCA
      DIMENSION   ZE(1)

      IF ((TH.LE.-90.0).OR.(TH.GE.90.0)) RETURN
      CALL PLTFR
      CALL VISNH
      CALL VISRS (Z1,ZE,Z2,NX,MX,NY,NY,TH,PLTCA)
      CALL PLTEJ
      RETURN

      END