Population data based on percentages or proportions. In geography, the vast majority of analyses of such data make use of standard statistical approaches, which, according to Aitchison (1986) should not be employed directly in the analysis of such data. Lloyd et al. (2012) AAAG 102, 6, 1251 highlight some problems associated with using standard approaches in the analysis of compositional data in population studies and outline some key log-ratio-based approaches for the transformation and the proper analysis of compositional data.