15.64.53  SPHERICAL 

SET POLAR [ON|OFF] [RADIANS|DEGREES|FULLCIRCLE=n|GRAD] [PEERMANENT]

This  sets  up to plot in spherical coordinates.  (THETA,R,PHI) instead of
(X,Y,Z).  The data in X is now interpreted as THETA, Y is intepreted as  R
and Z is intepreted as PHI.  The data is not modified, just reinterpreted.
     R=sqrt(X**2=Y**2+Z**2)
     THETA=ATAN2(Y,X)
     PHI=ATAN2(sqrt(x**2+Y**2),Z) 

NOTE:   There  is  no  universally  accepted  convention for THETA or PHI.
Various books use different conventons.  I have adopted a convention  that
gives THETA the same definition in both spherical and polar coordinates.

     1.  ON|OFF turn the spherical coordinates on or off.  (Default:ON)
     2.  PERMANENT - Sets these parameters permanently.
     3.  DEGREES...  - Selects angle representation (Default:DEGREES)
         A.  GRAD - (0-400)
         B.  DEGREES - (0-360)
         C.  PERCENT - (0-100)
         D.  RADIANS - (0-6.2831853)
         E.  FULLCIRCLE=n - (0-n)

You  still  set  the  limits  in  X,Y,Z coordinates, and automatic scaling
centers the origin.   When  you  plot,  the  axes  are  not  automatically
generated  if  spherical  coordinates  are on.  You must manually plot the
axes with the command:  PLOT AXES.