Editing Dimensional analysis (section)

=== Orientation and frame of reference ===
Similar to the issue of a point of reference is the issue of orientation: a displacement in 2 or 3 dimensions is not just a length, but is a length together with a ''direction''. (In 1 dimension, this issue is equivalent to the distinction between positive and negative.) Thus, to compare or combine two dimensional quantities in multi-dimensional Euclidean space, one also needs a bearing: they need to be compared to a [[frame of reference]].

This leads to the [[#Extensions|extensions]] discussed below, namely Huntley's directed dimensions and Siano's orientational analysis.