Properties can be DGN resident or database resident. DGN resident properties exist in the DGN file along with the feature to which it belongs. Database properties exist in an external database and follow the same conventions used in the MicroStation database interface. Both are addressed in the same way by the user. As the application designer, you can decide where properties should be stored.

Some features and properties are created automatically during the operation of OpenCities Map. For instance, if you import a SHP file, then those features are imported into the current file. Any properties in the associated DBF file are imported as DGN resident properties and exist in the active file.