The City needed geographical area definitions that were homogenous and non-political. The preexisting Neighborhoods feature class was defined to maintain homogenous areas of the City, but they were determined to be too discrete and numerous. Pertaining to size as well, it was believed that the geographical areas should not be so large, as to group together areas of the City that were dissimilar in character. Of particular importance, it was also a requirement that NSA geography was designed to permit analysis using Census data.
It was decided by the Planning Dept that adhering to Census Block Groups was the best approach. It was also determined that attempts to approximate the Planning Districts would also be beneficial. The approach to defining the NSAs was as follows: a) 2010 Census Block Groups were merged together to create each individual NSA, b) they were grouped in ways to maximize the ability to share boundaries with existing Planning Districts were ever possible. While most NSAs lie almost entirely within one Planning District, some NSAs are pretty equally split between two planning districts (notably D-1). In the case of D-1, PDR arbitrarily decided to put it with the other ‘Downtown’ NSAs.
The identification/naming of the NSAs was based upon the Planning Districts they most corresponded to, along with a sequential numbering assignment. Most NSA lie almost entirely within one Planning District, and where named from that Planning District. Names starting with "NO" are mostly in the North planning district; "NW" are mostly in the Near West planning district; "BR" are mostly in the Broad Rock planning district, etc... There’s no significance for the number following the planning district lettering used by NSAs (NO-1, NO-2, NO-3, etc). The number was just randomly assigned to further uniquely define the area subdivided within the Planning District, and has no relationship in terms to square area, population density, or anything.