Topography Spot Elevations [District of Columbia--Washington]
Mass Points (2008). The dataset contains DTM masspoints derived photogrammetrically to support 2' contours. Masspoints and breaklines were compiled from Spring 2008 aerial photography using softcopy photogrammetric techniques. Masspoint elevations are in based on NAVD US feet. Masspoints and breaklines were compiled to support generation of a TIN and the subsequent processing of 2' contours.