def plot_sino(self, ax=None, element=_def.LOSImpElt, Sketch=True,
                  Ang=_def.LOSImpAng, AngUnit=_def.LOSImpAngUnit, Leg=None,
                  dL=_def.LOSMImpd, dVes=_def.TorPFilld, dLeg=_def.TorLegd,
                  ind=None, multi=False,
                  fs=None, wintit=None, draw=True, Test=True):
        """ Plot the LOS in projection space (sinogram)

        Plot the Rays in projection space (cf. sinograms) as points.
        Can also optionnally plot the associated :class:`~tofu.geom.Ves`

        Can plot the conventional projection-space (in 2D in a cross-section),
        or a 3D extrapolation of it, where the third coordinate is provided by
        the angle that the LOS makes with the cross-section plane
        (useful in case of multiple LOS with a partially tangential view)

        Parameters
        ----------
        Proj :      str
            Flag indicating whether to plot:
                - 'Cross':  a classic sinogram (vessel cross-section)
                - '3d': an extended 3D version ('3d'), with an additional angle
        ax :        None / plt.Axes
            The axes on which to plot, if None a new figure is created
        Elt :       str
            Flag indicating which elements to plot (one per capital letter):
                * 'L': LOS
                * 'V': Vessel
        Ang  :      str
            Flag indicating which angle to use for the impact parameter:
                - 'xi': the angle of the line itself
                - 'theta': its impact parameter (theta)
        AngUnit :   str
            Flag for the angle units to be displayed:
                - 'rad': for radians
                - 'deg': for degrees
        Sketch :    bool
            Flag indicating whether to plot a skecth with angles definitions
        dL :        dict
            Dictionary of properties for plotting the Rays points
        dV :        dict
            Dictionary of properties for plotting the vessel envelopp
        dLeg :      None / dict
            Dictionary of properties for plotting the legend
            The legend is not plotted if None
        draw :      bool
            Flag indicating whether to draw the figure
        a4 :        bool
            Flag indicating whether the figure should be a4
        Test :      bool
            Flag indicating whether the inputs shall be tested for conformity

        Returns
        -------
        ax :        plt.Axes
            The axes used to plot

        """
        if self._dsino['RefPt'] is None:
            msg = "The sinogram ref. point is not set !"
            msg += "\n  => run self.set_dsino()"
            raise Exception(msg)
        return _plot.GLOS_plot_Sino(self, Proj='Cross', ax=ax, Elt=element, Leg=Leg,
                                    Sketch=Sketch, Ang=Ang, AngUnit=AngUnit,
                                    dL=dL, dVes=dVes, dLeg=dLeg,
                                    ind=ind, fs=fs, wintit=wintit,
                                    draw=draw, Test=Test)
Plot the LOS in projection space (sinogram)

        Plot the Rays in projection space (cf. sinograms) as points.
        Can also optionnally plot the associated :class:`~tofu.geom.Ves`

        Can plot the conventional projection-space (in 2D in a cross-section),
        or a 3D extrapolation of it, where the third coordinate is provided by
        the angle that the LOS makes with the cross-section plane
        (useful in case of multiple LOS with a partially tangential view)

        Parameters
        ----------
        Proj :      str
            Flag indicating whether to plot:
                - 'Cross':  a classic sinogram (vessel cross-section)
                - '3d': an extended 3D version ('3d'), with an additional angle
        ax :        None / plt.Axes
            The axes on which to plot, if None a new figure is created
        Elt :       str
            Flag indicating which elements to plot (one per capital letter):
                * 'L': LOS
                * 'V': Vessel
        Ang  :      str
            Flag indicating which angle to use for the impact parameter:
                - 'xi': the angle of the line itself
                - 'theta': its impact parameter (theta)
        AngUnit :   str
            Flag for the angle units to be displayed:
                - 'rad': for radians
                - 'deg': for degrees
        Sketch :    bool
            Flag indicating whether to plot a skecth with angles definitions
        dL :        dict
            Dictionary of properties for plotting the Rays points
        dV :        dict
            Dictionary of properties for plotting the vessel envelopp
        dLeg :      None / dict
            Dictionary of properties for plotting the legend
            The legend is not plotted if None
        draw :      bool
            Flag indicating whether to draw the figure
        a4 :        bool
            Flag indicating whether the figure should be a4
        Test :      bool
            Flag indicating whether the inputs shall be tested for conformity

        Returns
        -------
        ax :        plt.Axes
            The axes used to plot