Affine Geometry

<p><a href="http://bit.ly/2gzfYji" target="_blank">Source: Norman J. Wildberger, Associate Professor at the University of New South Wales, Sydney, Australia</a>

Only handles a notion of area.

If supplemented with the notion of parallelism, a notion of area.

Area is an affine concept.

Equally spaced lines in two directions give parallelograms which are all translates of a single one.

This presents the notion of relative areas, even if approximately (no metricisation at this level, ie. no distance, length, nor perpendicularity).</p>