This publication is the fourth in a series with this title. It addresses issues of building classifications of models of non-additive properties of geosystems (environmental well-being, "ecosystem health"). Examples of classification models of integrated assessment of ecological well-being of the water bodies, terrestrial ecosystems, are given. The authors propose a model-based classification of construction of the integral index of ecological well-being based on the method of summary indicators and the principles of ASPID methodology (analysis and synthesis of information indices under conditions of informational scarcity). Refs 27. Fig 1. Tables 4.