DC GIS harnesses the functionality of ArcGIS 9x, such as topology, cartographic representation and versioning.  It is critical to preserve the integrity and consistency of these rules and settings.  Therefore, all data transactions at OCTO GIS will use ArcSDE 9x on the geodatabase.  Agencies responsible for data maintenance should also utilize this standard for all data activities.  GIS files shared among agencies must also be in a geodatabase or in ArcSDE export format.  Shapefiles are not to be used, except for public data distribution.  Shapefiles may also be used for some minor interagency file sharing, except where the layers employ topology.