With geographic data, users can define important watershed boundaries using geospatial definitions. A user could either create boundaries or emergency planning zones (formerly defined as impact areas). Boundaries are used to define areas for aggregation and reporting. Emergency planning zones (EPZs) are used in the life loss computation to describe the geographic extent of specific warning systems and mobilization relationships. These typically correspond with Emergency Management Authorities, or whatever geographic region would contain the same warning system, or mobilization relationship.