Bentley's geospatial products support topology as a way of performing overlay analysis. This topology can be described as dynamic, or on-the-fly, because it is created when required for analysis and not saved with geometry. Bentley Map has the ability to store topology with geometry in the file. Topology is defined using Bentley Geospatial Administrator and maintained using the Bentley Map editing tools. While defining topology is optional, it better defines the data model and allows defining merge and join rules.