Ichnography
Ichnography (Gr. τὸ ἴχνος, íchnos, "track, trace" and γράφειν, gráphein, "to write"),[1] 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.
Ground plans can help in creating sufficient floor space, especially for larger designs where appropriate planning is needed such as with Depot and shops, however modern architectural large-scale designs are usually done by means of computer with certain dedicated software. Ichnography today can crudely be used for small-scale plans such as Garden and Bedroom layouts,sometimes with 3D sketches. They may be used by children and other 'non-professionals' as a way to help express their imagination of design or as a form of geometrical play.
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References
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.