- 3 - 
Data Acquisition Operations 
Production of a new map begins with the search of a document file containing known 
ground control and identification data, cadastral data, and previous contour maps, etc., 
which may be available. This data has usually been manually recorded for flight and 
ground-control survey planning. In addition, film, camera, and diapositive printer 
calibration, as well as lens distortions, camera-platen flatness, atmospheric refrac 
tion data, and all other measured system distortions are usually on file for use. Much 
of this data can be converted and stored in digital form. At present, much of this 
calibration data is made available in various non-standard forms from manufacturing 
and testing organizations. Considerable digital data output from measuring equipment 
is handwritten and then keypunched. Much of the measuring equipment could conceivably 
be automated to produce digital data directly. This change could be used to increase 
the accuracy of this data by eliminating manual reading and keying errors, when such 
improved mapping quality is justified. 
Flight Film and Data Acquisition 
Acquisition of accurate aerial images remains a photographic camera process. A 
digital recording substitute for this process appears remote. In addition to film 
acquisition, the digital recording of camera flight station data is needed. The appro 
ximate location, and attitude, if obtained in digital form, would reduce accidental 
errors which occur in transferring this data to the computer for use with an analy 
tical resection and orientation program. 
Field Data Acquisition 
In field-data acquisition, instruments such as theodolites, transits, distance 
measuring equipment, barometric devices, tapes and timers are used. These 
instruments are usually manually read and recorded. Each of these data-recording 
operations is potentially mechanizable; but again, key-punching of handwritten field 
data with its potential recording errors is the digital conversion technique primarily 
used because of its low cost. 
Errors Inherent in Manual Data Acquisition 
Thus, most data acquisition operations are now, primarily, a manual data-recording 
operation. Keying error rates of 1/500 to 1/1000 are not uncommon in key-punch 
and verification operations. These accidental errors are a source of major concern. 
Analytical control extension and adjustment can minimize but not remove the effects 
of such accidental errors in the source data acquired. Only if data is automatically 
recorded and converted to digital form will such errors be reduced. 
Photogrammetric Data Processing 
I would next like to discuss the progress that has been made in the development of 
a Digital Automatic Map Compilation System, using this acquired data, to convert 
aerial diapositives to contour and orthophoto manuscripts. This development work, 
at Kingston, New York, has been largely supported by U. S. Army (GIMRADA) and 
IBM research funds; other agencies have assisted in collateral application areas. 
The DAMC System (Figs. 1, 2) is now digitizing and processing digital photographic 
input data of varying quality up to a resolution of 400 scan lines per inch. A potential