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METHODOLOGIES

Diversity: Shannon index and evenness

How balanced the formation mix is.

Intermediate 1 min read diversityformationsstatistics

Shannon diversity summarises how many classes there are and how evenly area is spread between them.

Method

H = −Σ pᵢ · ln pᵢ, where pᵢ is the area share of formation i.

Evenness J = H / ln(k), where k is the number of formations. J = 1 means perfectly even; values near 0 mean one class dominates.

How to interpret it

Compare J between landscapes or years, not as an absolute quality score.

Limits. Depends on how formations were classified at mapping time.

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