It is this second method which is used in DLG-3 transfers. In most cases a DLG-3 spatial object will have one code which identifies a real world entity. The codes which identify entities are listed for each theme. Other DLG-3 codes are converted to appropriate values for other attributes. Attributes will vary with the DLG-3 theme.
Additional attributes provide additional descriptive and parameter information about the entity.
These additional attributes will differ with theme. This contains records indicating that a feature is coincident with a feature in another DLG-3 theme. For example, roads are frequently coincident with boundaries and the Public Land Survey. The TVP specifies that attributes which can have more than one value be separated into their own Attribute Primary module. These DLG ' s store information in companion text files which serve as input to the conversion process.