ABSTRACT
We have discussed at some length the projections of a cloud of profiles onto a single principal axis, the best-fitting straight line. In practice you will find that most of the reported CA displays are two-dimensional, usually with the first principal axis displayed horizontally (the x-axis) and the second principal axis vertically (the y-axis). In general, the projections may take place onto any low-dimensional subspace, but the two-dimensional case is, of course, rather special because of our two-dimensional style of displaying graphics on computer screens or on paper. In the Computational Appendix there are also some examples using the R programming language to do CA graphics in three dimensions (e.g., Exhibit B.5 on page 235).
