The SPATIAL RATIOS rule: Grundflächenzahl GRZ / Geschossflächenzahl GFZ

In playing around with the Soduko / Magic Squares to formulate rules that dictate the spatial distribution of densities over the site, we might include the ideas from the way Germany controls densities with their Grundflächenzahl (GFZ = Site Coverage, not "Site Density Ratio" in the picture below, sorry) and Geschossflächenzahl (GRZ = untranslatable, something like "Site Story Ratio"). German pronouciation below.

SCR (site coverage ratio) comes first, then the SSR (site story ratio): if a site has a SCR (site coverage ratio) of 1.0 (=100%) and a SSR (site story ratio) of 1.0 (=100%) you're allowed to build 1 story high on 100% of the site. If a site has a SCR of 0.5 (=50%) and a SSR of 1.0 (=100%), you're allowed to build two stories on 50% of the site. And so on.... quite self explanatory really. But you have to be German to come up with it, I guess. Haven't seen anything like SSR in Australia.

SCR and SSR together could translate into a "Site Density Ratio" (SDR), but I haven't worked out how (yet).

German pronounciation-links:
Grundflächenzahl: http://tts.imtranslator.net/FHud (give it a moment to load and it talks to you)
Geschossflächenzahl: http://tts.imtranslator.net/FHug