ABSTRACT
All collectors and users of geographical data, whether they are in commerce, administration or research, face a major problem in combining data collected for different zonal systems. Data of many kinds in the social and environmental sciences are collected for areal units, but the systems of units used differ between different sets and are subject to change over time. This is a perennial source of difficulty in comparing data originating from two different sources, in studying change over time, and in studying relationships between variables of all types. This paper introduces a project intended to develop improved methods for tackling this problem.
