Computer Network: Formats and Mediums 
  
A firm specializing in photogrammetrically-collected digital data must 
be able to provide the output in a language, format and medium that will 
be compatible with almost any client's computer hardware and software; 
with the current proliferation of systems, this can become a very ex- 
pensive nightmare. AAI has developed a unique computer network system 
which includes some specialized data communications software; we have 
linked the DEC PDP 11/73 through an RS232 hard cable interface with an 
inhouse IBM PC-XT and HP86B. This link operates from a single serial 
port on the DEC through two triple switch boxes which also provide hook- 
up to a phone modem. As a result, we are able to provide ASCII files 
in DEC, IBM or HP format on 8 inch, 5 inch or 3 inch disks, in hardcopy 
via the LA50 printer, or on 800/1600 BPI 10 inch magnetic tape reels. 
Most personal micro and mainframe computers will be able to read one of 
these formats and mediums, thus enabling AAI to provide digital data- 
base services to almost any client in almost any field. 
This same network is used to transfer information to various stations 
for different operations during the execution of a complete project, 
automating approximately 65% to 75% of the work normally done by 
traditional methods. 
Accuracy 
The utility and accuracy of this integrated photogrammetric system as an 
automated data collection/data generation tool is dependent upon the 
accuracy of the data collected by the analytical instrument - the KERN 
DSR-11. This, in turn, is based upon the calibrated accuracy of the 
camera, the analytical instrument, and the precision and accuracy of 
control information used in absolute orientation of models. The KERN 
DSR-11 calibrates to within 1 micron RMS for both plates, meeting re- 
quirements for classification as a first-order plotter. 
In the fall of 1985, AAI was asked to do a topographic map of a City of 
Phoenix maintenance yard in preparation for on-site and off-site engi- 
neering design; the map was produced photogrammetrically and ground 
checked by a field survey crew. The flying height was 1080 feet + above 
mean terrain, yielding a photo scale of 180 from which 30 scale maps 
were generated. Approximately 23 catch basins exist in the project in 
addition to buildings, curb and gutter, and other easily measurable hard 
features; two blueprints of the planimetric data were made marked with 
locations for X,Y and Z data collection independently by a stereo oper- 
ator and a field crew equipped with a Wild T2 theodolite, a Topcon DMA-2 
and a Leitz C3-A level. The prints containing the acquired data were 
given directly to Mr. Jeff Andrews, Principal Registered Surveyor, for 
analysis and comparison of coordinates; results indicated that photo- 
grammetrically acquired vertical data was within .03 of a foot of data 
acquired by traditional field methods and therefore quite adequate for 
civil design. 
Systematic Project Approach 
  
When a first-order analytical instrument forms the kernel of a data 
collection, analysis and manipulation system, it is possible to plan an 
entire project around the system in such a way that 65% to 75% of the 
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