(self, vx, vy=None, vz=None)
return vmin, vmax
Get the min and max value of theta of the parallel to cover the
        field of view.

        Input:
          - the normalized vector of the direction of the center of the
            projection, in the reference frame of the graticule.
        Return:
          - vmin,vmax : between 0 and pi, vmin<vmax, the interval of theta
                        for the parallels crossing the field of view
Get the min and max value of theta of the parallel to cover the
        field of view.
Get the min and max value of theta of the parallel to cover the field of view .
def get_parallel_interval(self, vx, vy=None, vz=None):
        """Get the min and max value of theta of the parallel to cover the
        field of view.

        Input:
          - the normalized vector of the direction of the center of the
            projection, in the reference frame of the graticule.
        Return:
          - vmin,vmax : between 0 and pi, vmin<vmax, the interval of theta
                        for the parallels crossing the field of view
        """
        if vy is None and vz is None:
            vx, vy, vz = vx
        elif vy is None or vz is None:
            raise ValueError("Both vy and vz must be given or both not given")
        a = np.arccos(vz)
        fov = self.proj.get_fov()
        vmin = max(0.0, a - fov / 2.0)
        vmax = min(pi, a + fov / 2.0)
        return vmin, vmax
def get_parallel_interval ( self , vx , vy = None , vz = None ) : if vy is None and vz is None : vx , vy , vz = vx elif vy is None or vz is None : raise ValueError ( "Both vy and vz must be given or both not given" ) a = np . arccos ( vz ) fov = self . proj . get_fov ( ) vmin = max ( 0.0 , a - fov / 2.0 ) vmax = min ( pi , a + fov / 2.0 ) return vmin , vmax