SUBROUTINE  PLTSV (FU,NP,NT,O,PR,PL)

C     [SPHERICAL VIEW]
C     PROGRAM TO PRODUCE A PERSPECTIVE DRAWING OF A SINGLE VALUED
C     FUNCTION DEFINED OVER A SPHERICAL SURFACE, SO AS TO EXHIBIT
C     THE ARCS OF LATITUDE AND LONGITUDE.
C     FU(NP,NT) ARRAY OF FUNCTION VALUES
C     NP        NUMBER (=2*N) OF POINTS ON ONE LATITUDE
C     NT        NUMBER OF POINTS ON ONE LONGITUDE
C     O(3,3)    ORTHOGONAL ROTATION MATRIX
C     PR        PROJECTION SUBROUTINE
C     PL        PEN MOVEMENT SUBROUTINE
C     [22-NOV-74]

      EXTERNAL    PR,PL
      LOGICAL*1     B,C
      DIMENSION   FU(1),O(3,3)

      NH=NP/2
      CALL VISNP (PH,TH,JP,IT,NP,NT,O)
      IF (TH.GT.(1.57079)) GO TO 10
      I1=1
      I2=IT
      I3=IT
      I4=NT
      S1= 1.0
      S2=-1.0
      GO TO 12
   10 I1=IT
      I2=NT
      I3=1
      I4=IT
      S1=-1.0
      S2= 1.0
   12 J1=JP
      J2=JP+NH
      J3=JP-NH
      J4=JP
      CALL PR (R,P,0.1,TH,PH+0.05,O)
      B=((-0.25).LT.P).AND.(P.LE.(0.25))
      C=.NOT.B
      CALL VISNH
      CALL VISSS (FU,J1,J2,NP,I1,I2,NT,1,-1,S1,B,O,PR,PL)
      CALL VISSS (FU,J1,J2,NP,I1,I2,NT,1, 1,S2,B,O,PR,PL)
      CALL VISSS (FU,J1,J2,NP,I3,I4,NT,1, 1,S2,B,O,PR,PL)
      CALL VISSS (FU,J1,J2,NP,I3,I4,NT,1,-1,S1,B,O,PR,PL)
      CALL VISNH
      CALL VISSS (FU,J3,J4,NP,I1,I2,NT,-1,-1,S1,C,O,PR,PL)
      CALL VISSS (FU,J3,J4,NP,I1,I2,NT,-1, 1,S2,C,O,PR,PL)
      CALL VISSS (FU,J3,J4,NP,I3,I4,NT,-1, 1,S2,C,O,PR,PL)
      CALL VISSS (FU,J3,J4,NP,I3,I4,NT,-1,-1,S1,C,O,PR,PL)
      RETURN

      END