Hydrography Centerline. The dataset contains polygons representing planimetric hydrography centerline, created as part of the DC Geographic Information System (DC GIS) for the D.C. Office of the Chief Technology Officer (OCTO). These features were originally captured in 1999 and updated in 2005. The following planimetric layers were updated: - Building Polygons (BldgPly) - Bridge and Tunnel Polygons (BrgTunPly) - Metro Entrance Points (MetroEntPt) - Obscured Area Polygons (ObsAreaPly) - Railroad Lines (RailRdLn) - Road, Parking, and Driveway Polygons (RoadPly) - Sidewalk Polygons (SidewalkPly) - Under Construction Areas (UnderConstPly) - Wooded Areas (WoodPly) The following planimetric layers are new: - Horizontal and Vertical Control Points (GeoControlPt) - Hydrography Center Lines (HydroCenterLineLn). METADATA CONTENT IS IN PROCESS OF VALIDATION AND SUBJECT TO CHANGE.