NACh (Normalised Angular Choice) and NAIn (Normalised Angular Integration) were introduced in Hillier et al. (2012). To create them first calculate Choice and Total depth (Tools -> Segment -> Run Angular Segment Analysis..., include choice), create the two new attributes/columns (Attributes -> Add Column) and finally set their formulas (Attribute -> Update Column).
According to Hillier et al. (2012) the equation for NACh is:
NACh = log( ACH + 1) / log( ATD + 3)
where ACH = Angular Choice and ATD = Angular Total Depth.
Thus the formula in depthmapX needs to be:
log(value("T1024 Choice") + 1) / log(value("T1024 Total Depth") + 3),
assuming that the analysis carried out was Angular Tulip analysis with 1024 bins and no radius limit.
The equivalent for NAIn is:
NAIn = NC ^ 1.2 / ATD
where NC = Node Count and ATD = Angular Total Depth.
Thus the formula for depthmapX needs to be:
value("T1024 Node Count")^1.2 / value("T1024 Total Depth")
References:
- Hillier, W. R. G., Yang, T., & Turner, A. (2012). Normalising least angle choice in Depthmap - And how it opens up new perspectives on the global and local analysis of city space. Journal of Space Syntax, 3(2), 155–193.