Its value gives the spacing between the bottom edge of the title and a reference point specified by the TextGapType attribute (by default, the top edge of a box enclosing all other parts of the annotated grid). Positive values cause the title to be drawn outside the box, while negative values cause it to be drawn inside.
The TitleGap value should be given as a fraction of the minimum dimension of the plotting area, the default value being 0.05.
The text used for the title is obtained from the Plot
’ s Title attribute.