Ichnography (Gr. τὸ , íchnos, "track, trace" and γράφειν, gráphein, "to write"), pronounced ik-nog-rəfi, in architecture, is a term defined by Vitruvius (i.2) as the ground plan of the work, i.e. the geometrical projection or horizontal section representing the plan of any building, taken at such a level as to show the outer walls, with the doorways, windows, fireplaces, etc., and the correct thickness of the walls; the position of piers, columns or pilasters, courtyards and other features which constitute the design, as to scale.