SUBROUTINE  PLTSP (PH,TH,P)

C     [SPHERICAL POLAR]
C     CHANGE THE ANGULAR VARIABLES PH,TH TO THE CARTESIAN COORDINATES
C     X,Z SO AS TO DEFINE DIRECTLY IN SPHERICAL POLAR COORDINATES POINTS
C     WHICH LIE UPON THE SURFACE OF A CONSTANT SPHERE AND GRAPH THEIR
C     PROJECTION ON THE X-Z PLANE. PH,TH ARE BOTH SUPPOSED TO LIE IN
C     THE RANGE 0.0 .LE. PH,TH .LE. 1.0, SINCE THIS IS THE RANGE ASSUMED
C     BY SUCH SUBROUTINES AS THE CONTOURING PROGRAMS.
C     [16-NOV-74]

      LOGICAL*1     P
      DATA        HX,HY/4.50,3.25/

      R=HY
      THE=3.14159*TH
      PHI=6.2831*PH
      X=R*SIN(THE)*COS(PHI)
      Y=R*SIN(THE)*SIN(PHI)
      Z=R*COS(THE)
      CALL PLTMS (X,Z,(P.AND.(Y.GT.0.0)))
      RETURN

      END