AUTHOR=Secu Cristian Vasilică , Pîrnău Radu Gabriel TITLE=Ranking Territorial Units Using Entropy-Based Pedodiversity JOURNAL=Spanish Journal of Soil Science VOLUME=Volume 16 - 2026 YEAR=2026 URL=https://www.frontierspartnerships.org/journals/spanish-journal-of-soil-science/articles/10.3389/sjss.2026.15664 DOI=10.3389/sjss.2026.15664 ISSN=2253-6574 ABSTRACT=The pedodiversity concept integrates diversity indices and GIS techniques to assess the spatial heterogeneity of soils. This study proposes using pedodiversity indices for Romania’s geographic regions and relief units to evaluate their connectivity. Keeping the map scale, the soil type-subtypes vector was simplified to soil types. Aggregation reduced the number of polygons from two taxonomic categories only for certain taxa (variable taxa), while constant taxa remained unchanged. Low connectivity in parts of the Southern and Eastern Carpathians and the Western Plain suggests the presence of numerous subtypes within soil assemblages, whereas arid regions (e.g., Dobrogea Plateau), characterized by lower taxonomic variability, display strong connectivity. The connectivity index ranks landform units as follows: plains < plateaus < Carpathians < Subcarpathians, differing from the geographic regions hierarchy. Among the indicators tested, the connectivity index exerts the strongest influence on spatial ranking, while the diversity index proves less decisive.