Single‐species distributional patterns have been well studied and quantified using a negative binomial model. However, it is still unclear how to quantify multi‐species distribution patterns. A previous study (Chen et al. 2019) developed a simple conspecific‐encounter index for quantifying multi‐species distributional aggregation patterns when biodiversity data are collected in a consecutive scheme along line transects. Here, through simple derivation, we reported that the previously proposed conspecific‐encounter index had a close association with Moran's I index, which has been widely applied in spatial ecology for describing spatial autocorrelation of ecological data. Our proof unified the conspecific‐encounter index that is applied under the context of line‐transect sampling and Moran's I index that is applied under the context of spatial ecology. The unification sheds light on the development of new statistical metrics for quantifying biological diversity and distribution patterns when line transects are used in field surveys.