def plot_xtime(self, y, x='time', label='default', labelx=None,
                   labely=None ,title=None, shape='.', logx=False,
                   logy=True, base=10):
        '''
        make a simple plot of two columns against each other.

        An example would be instance.plot_xtime('PB206', label='PB206 vs t_y'
        Recomend using the plot function DataPlot.plot() it has more
        functionality.

        Parameters
        ----------
        Y : string
            Column on Y-axis.
        X : string, optional
            Column on X-axis.  The default is "time".
        label : string, optional
            Legend label.  The default is "default".
        labelX : string, optional
            The label on the X axis.  The default is None.
        labelY : string, optional
            The label on the Y axis.  The default is None.
        title : string, optional
            The Title of the Graph.  The default is None.
        shape : string, optional
            What shape and colour the user would like their plot in.
            The default is '.'.
        logX : boolean, optional
            A boolean of weather the user wants the x axis
            logarithmically.  The default is False.
        logY : boolean, optional
            A boolean of weather the user wants the Y axis
            logarithmically.  The default is True.
        base : integer, optional
            The base of the logarithm.  The default is 10.

        Notes
        -----
        For all possable choices visit,
        <http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.plot>

        '''
        if label is 'default':
            lab_str=y
        else:
            lab_str=label

        try:
            self.get(x)
        except KeyError:
            x='age'

        DataPlot.plot(self,x,y,legend=lab_str,labelx=labelx, labely=labely,
                      title=title, shape=shape,logx=logx, logy=logy, base=base)
        '''
        print X,Y
        xdat=self.get(X)
        ydat=self.get(Y)
        self.xdat = xdat
        self.ydat = ydat


        plot(xdat,log10(ydat),label=lab_str)
        legend()
        '''
make a simple plot of two columns against each other.

        An example would be instance.plot_xtime('PB206', label='PB206 vs t_y'
        Recomend using the plot function DataPlot.plot() it has more
        functionality.

        Parameters
        ----------
        Y : string
            Column on Y-axis.
        X : string, optional
            Column on X-axis.  The default is "time".
        label : string, optional
            Legend label.  The default is "default".
        labelX : string, optional
            The label on the X axis.  The default is None.
        labelY : string, optional
            The label on the Y axis.  The default is None.
        title : string, optional
            The Title of the Graph.  The default is None.
        shape : string, optional
            What shape and colour the user would like their plot in.
            The default is '.'.
        logX : boolean, optional
            A boolean of weather the user wants the x axis
            logarithmically.  The default is False.
        logY : boolean, optional
            A boolean of weather the user wants the Y axis
            logarithmically.  The default is True.
        base : integer, optional
            The base of the logarithm.  The default is 10.

        Notes
        -----
        For all possable choices visit,
        <http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.plot>