
Journal for Geometry and Graphics 7 (2003), No. 2, 137144 Copyright Heldermann Verlag 2003 An Algebraic Equation for the Central Projection Arne Dür Institut for Mathematics, University of Innsbruck, Technikerstr. 25, A 6020 Innsbruck, Austria, arne.duer@uibk.ac.at A necessary and sufficient condition for a centralaxonometric reference system to be the image of a positively oriented orthonormal frame under a central projection is given by a single complex equation. The presented equation is an analogon of the Gauss equation that characterizes the reference system of an orthogonal axonometry. Keywords: central projection, central axonometry, Gauss equation. MSC: 51N05. FullTextpdf (104 KB) for subscribers only. 