€) 
deling, 
od 
lone 
€) 
nd 
tion 
ation 
independent scaling of two axes. The automatic table works in several 
modes: track, for continuous line drawing; line, for automatic 
plotting of straight lines between two points; dashed line, for 
automatic plotting of dashed lines; cross, for automatic symbol 
plotting; off line, in which punched paper tape is produced for 
automatic drafting of digital data. 
The DC-2 is an interactive digitizer graphic system which may be 
added to the PG2-AT. It permits computational determination of 
absolute orientation, automatic plotting of map symbols, digital 
recording of points and profiles, continuous digital recording of 
planimetry at variable point density, and control of the AT table 
for automatic drafting. 
MARK HURD AERIAL SURVEYS 
William R. Seestrom 
The New Jersey Wetlands project, a joint venture with Earth 
Satellite Corporation, was undertaken to determine the extent of 
coastal wetlands as directed by the New Jersey Department of Environ- 
mental Protection. The total area surveyed comprised approximately 
1800 square miles. Aerial photography was obtained at 1:12,000 scale 
using a dual camera setup to obtain simultaneous exposures with one 
camera obtaining infrared color photography and the other camera obtaining 
natural color photography. Using the original transparencies for the 
two types of aerial photography, and photographic enlargements at 
1:2400 scale, a comprehensive species delineation and upper wetlands 
boundary determination was made through photointerpretation. 
Base maps were prepared at a scale of 1:2400 consisting of a 
Screened image of the rectified aerial photography and an overprint 
of species lines, upper wetlands boundary, biological high water line, 
grid lines, names data, and appropriate border data. The base maps 
were used for preparing special overlays of property lines and 
depiction of wetlands features as portrayed on 1877-87 maps and 
1930-32 aerial mosaics. 
NORTH PACIFIC AERIAL SURVEYS 
Anthony B. Follett 
During 1974 NPAS embarked on a program to acquire speculation 
photography at high altitudes of as much of Alaska as possible. 
The effort has obtained black and white vertical aerial photography 
primarily at scales of 1:63,360 and 1:76,000 of nearly one-third of 
the State of Alaska. This represents almost 200,000 square miles of 
terrain. 
-65-