1. a generalized, user-defined view of the data related to applications 2. a formal method for arranging data to mimic the behavior of the real-world entities they represent —note (GIS) fully developed data models describe data types, integrity rules for the data types, and operations on the data types; some data models are triangulated irregular networks (TIN), images, and georelational or relational models for tabular dataThis definition last updated 10/25/2008