combine isoline and axis geoms about ordr

[corybrunson]

Resolved as of 7ae7345. (But do raise future issues if functionality fails!)

[jtr13]

At least from a user perspective (if not a technical one) it seems very similar to a ggplot2 scales function... maybe + scale_rows(subset = ...) with name =, labels =, breaks = , and other relevant parameters from the scale_ functions.

[corybrunson]

@jtr13 that's definitely right from the user perspective. I looked into this possibility a while back, and i think the right way to think about it is that, while we may read the variable axes of a biplot as we do the coordinate axes of a scatterplot, their role is that of graphical elements of the plot rather than the coordinate scales with respect to which the graphical elements are rendered. This is a mechanical constraint of the Scale* (and Coord*) ggproto objects in ggplot2, but even in theory it is necessary because biplots usually only approximate the relationships between the case markers and the variable axes.

That said, it might make sense to adapt some of the scale_* parameters in addition to the aesthetic parameters from other complicated plot layers. Thank you for suggesting it!

[jtr13]

That makes sense, I appreciate the explanation!