DC GIS has updated the aerial photography and planimetric data layers on a regular basis. The city’s original capture was in 1999, with updates in 2005, 2008, 2010, and 2013. The 1995 and 1999, NCPC mapping efforts were compiled at a map scale of 1:1000 (1 inch = 83.33 feet) and the updates between 2005 and 2010 were compiled at 1:1200 (1 inch = 100 feet). In the spring of 2015, DC contracted for LiDAR, oblique imagery and new planimetrics. The District now uses Maryland State Plane Coordinates NAD 1983/91 and NAVD 1988, coordinates in meters at ASPRS standards for large scale mapping at 1:1200.

• Documentation for Features, Quality Control & Attribution (Data Dictionary)