The initial survey showed a high level of spatial heterogeneity in the location of industries in Jepara. For subsequent sampling and more detailed analysis of a subset of these enterprises, the area was divided into squares, each of which would be independently surveyed. The theoretical optimal size of the squares was calculated using the standard interpolation method, with weighted distances. Details are given in Annex 1 and the resulting grid is illustrated in Figure 2. The spatial heterogeneity is so extreme that 80% of the workshops are located in only 17% of the squares. The remaining squares have a much lower.
