I haven't ran this through any kind of rigorous analysis to determine if there are categories that ought to be included or removed. I mentioned at the site that I am glad he didn't include density, as the others are constructed factors which then become amenities that are then revealed through demand --> cost --> density. This is something that will continue to occupy my brain for sometime in thinking how to make it useful as an analytical tool.
This also might have just been a happy accident, but the ranges of density that become the color coded lines correlate pretty directly to T-zones from the transect, which would suggest the direct correlation between most dense T-zone with broadest shape produced. I don't know if he was applying local Des Moines neighborhoods here, but I would have downtown higher for population diversity, at least in the ideal sense.
I've been thinking about this while writing my last post for the Book Club. It struck me that if you think about it in 3-D with this graphic laying flat and arising to a point, this has some correlation to the Maslow-Urban pyramid I have created:
Not so much in terms of specifics, but rather that the greater volume of shape equates to the amount of people looking for those amenities (needs/wants/etc.). In the Maslow pyramid above, as humans we ALL have the primal needs for shelter, food, water, etc. These have to be met for the City to even be Viable.
However, with the pentagram above, the greatest volumes are formed by areas of the City that have all of the features listed. The bigger the shape/volume equals higher demand, which means real estate value, which then gets translated by the market into density. Then if density is lacking in certain areas that otherwise have the amenities, there are potentially identifiable reasons for that. Likewise, if increased density is desirable, the amenities such as connectivity or public realm must be identified and improved.
I should also add that diversity of population is still the one that I'm struggling with. It still strikes me as a resulting product, or output, rather than an input, which connectivity clearly is. In fact, all of these could stem in many ways with connectivity and its various scales, speeds, modes, distances, etc.
I just posted this comment over on the Des Moines site to keep the dialog going, because as I mention I think there is something profound here, especially with further distillation. I'll post it below as well, to get the dialogue going with readers here:
Sorry to keep pestering you, but I think there is something really profound here, but it just has to be elucidated a bit. You are right that density is relative. There are good forms of density and bad forms. In my opinion, the bad density is a product of a real estate delivery and city building system that has lost its way.
Where there should be a direct relationship between amenity and value/density, which is what your diagram shows, and how we know infrastructure and development at least SHOULD exist, there is not a direct relationship in what we might label as the 20th century city for shorthand. In fact, there is no relationship or guiding force. In many cases, it is delivering density where it doesn't want to be (and getting slums) or not correctly identifying the barriers to why density ISN'T happening in areas that have levels of amenity like high connectivity, etc.
I am still struggling with the two diversities, I guess. These strike me as outputs or resultant products of various forces rather than the inputs. I think this can get really strong if we're able to distill a similar diagram strictly to inputs. I guess the challenge with that is the feedback loops inherent in complex systems such as cities. I'm wondering, are there more elements to this equation? If so, what might they be? Or are there less, and they all revolve around connectivity and its various permutations?