*3.1. Hierarchical Structure Tree*

The basis of the hierarchical structure tree (Figure 3) was a set of criteria proposed in the papers on assessment of area in terms of the location of single-family residential buildings with solar installations [60,61]. Importantly, the groups of criteria and main criteria were developed on the basis of the subject matter literature review i.e., [62–64] and selected legal provisions. Fifteen main criteria were proposed, taking into account the distance from selected facilities, properties of plots. Moreover, selected climatic factors likely to affect the efficiency of solar installations have been taken into consideration. The last decision level, i.e., sub-criteria have local character and depends on the research area, the subcriteria of these figure were proposed on the basis of spatial analysis of Bialystok.

**Figure 3.** Hierarchical structure tree. \* The last decision level (in frame) depends on the research area; the subcriteria of these figure were proposed on the basis of spatial analysis of Bialystok. Source: author's own work based on [60,61].

A hierarchical structure tree was developed, in which the following levels were distinguished:


Importantly, the groups of criteria presented in Figure 3, main criteria and sub-criteria, the hierarchical structure tree presents only the so-called soft criteria, i.e., factors enabling the suitability assessment of a given area in terms of the location of the selected investment.
