The grouping of attributes based on an analysis of the individuals that possess or lack those attributes; e.g. in plant ecology the grouping of species according to their presence, absence, or relative abundances at different sample sites. The term is used particularly in numerical vegetation classification, and is sometimes referred to as a species classification. Ordination methods may similarly be described as either plot (individual) or species (attribute) ordinations. In plant ecology especially, inverse classifications are often used to complement normal analysis. Thus, data will be analysed using both approaches and coincidence between the final groups examined. It is assumed that high coincidence implies the recognition of an important ‘type’ community or ‘nodum’. In its concept, nodal analysis is a method based on these principles. See also Q-technique; compare normal analysis; and R-technique.
Subjects: Plant Sciences and Forestry — Ecology and Conservation.