Typology and Representation of Alterations in Territorial Units: A Proposal

This article proposes a typology of boundary changes in territorial units at two points in time. The different types of changes are organized in a hierarchy and represented homogeneously, independently of the number of territorial units involved and of the changes to them. Each alteration is described precisely and unambiguously, and it is codified to allow the information to be treated automatically. In addition to providing efficient storage of the information about these changes, a canonical representation facilitates the automatic detection of inconsistencies in the database. At the same time, the typology allows us to define backward and forward equivalence rules, which helps in the task of generating homogeneous time series about territorial unit characteristics, such as population or surface area, or generating the full genealogy of a territorial unit over time. We also offer an application of the proposal to inconsistencies and error detection in the database Alterations to the Municipalities in the Population Censuses since 1842 from the Spanish National Statistical Institute (INE).