Aggregation

Aggregation is the process of grouping spatial data at a level of detail or resolution that is coarser than the level at which the data were collected. For example, a national census collects sociodemographic and socioeconomic information for households. However, to ensure confidentiality during dissemination, such information, by necessity, is aggregated to various census geographies that differ in size. These geographies include, among others, census tracts (or “districts,” as they are called in some countries), municipalities (or “shires”), and provinces or states. The outcome from aggregation is always the same: There is a loss of spatial and attribute detail through the creation of coarser spatial data consisting of fewer observations. While such data may be a desired outcome for some tasks, this is not always ...