Plotting of 3D output variables

[rosiealice]

In the spirit of describing the full range of things we might want an ideal diagnostics package to do, fairly high up is to have a means of plotting out the higher oorder output variable from FATES. These are the ones that have an additional dimension other thatn lat,lon,time. Like PFT, or size class, or age class, etc.

We would need to think about what plots would actually look like for this. As a first cut, you might think, say for the PFT indexed variables.
1- TRENDS: maybe disaggregated per PFT?
2- MAPS: an x by y subplot arrangement rather than a single map. This would likely need specification of the number of plots in each row, or something like that?
3- SEASONAL CYCLES: Plot one line oer PFT?
4- COMPARISON MAPS: This is possibly the hardest? Maybe a column for model A, a column for model B and a a column of plots for differences? It wouldn't look great, but you could always maybe disallow 3D variables from the comparison?

As ever, i don't know if this is easy or massively annoying. The variables should be self describing at least.

I am leaving off here support for 4D variables. These exist, but I can't think of any sensible ways to visualize them in a mass-produced and global manner. But I think that is fine for now as one would normally have quite niche applications for those.