J. V. Sharp* 
R. L. Christensen 
W. L. Gilman 
F. D. Schulman 
Data Systems Division 
International Business Machines Corp. 
Kingston, New York 
Automatic Map Compilation 
Using Digital Techniques 
Technical feasibility of the digital technique has been demonstrated 
by producing contour maps having a C-factor greater than 
250 in less than an hour per model. 
(Abstract is on page 226) 
Introduction 
uring the period of this Digital Auto 
matic Map Compilation (DAMC) de 
velopment, several stereo aerial models from 
test areas were successfully compiled into 
contour maps and orthophotos. These were 
prepared with a digital map compilation sys 
tem consisting of an IBM 7094 computer 
(Figure 3) and an experimental digital dia 
positive scanner-printer, combined with a 
WILD STK-1 stereocomparator (Figure 1). 
Technical feasibility of the digital compila 
tion process was established by the successful 
production of contour manuscripts and ortho 
photos, which was the objective of this ex 
perimental effort. The digital map compila 
tion process was tested with several sets of 
stereo aerial photographs representing various 
types of terrain and camera orientation. 
Present digital compilation methods pro 
vide substantial improvement in the rate of 
handling large quantities of photo data in a 
stereo pair, with a resultant map compilation 
time on the order of tens of minutes, depend 
ing on the programming system used. Two 
major programming systems were developed: 
the sequential system, which is accurate and 
fast, and the predictive system, which is 
presently faster but less accurate in map 
compilation. 
The sequential programming system is an 
in-line operational approach which divides 
the map compilation process into five phases: 
1. Resection-orientation. 
2. Rectification. 
3. Digital image correlation and parallax 
calculation. 
4. Contouring and orthophoto correction. 
5. Tic mark insertion. 
A block diagram of the DAMC sequential 
system is shown in Figure 9. The resection- 
orientation program determines the camera 
orientation and is based upon the Church 
resection method. The tilt, swing, azimuth, 
and nadir location are computed for each 
photograph of the stereo pair. The output of 
this program is used to align the stereo- 
diapositives properly on the WILD STK-1 
stereocomparator for scanning parallel to the 
flight line and to provide certain parameters 
which are required for rectification. 
The rectification program repositions the 
digitized photographic data to compensate 
for displacement caused by tilt and scale. 
* Presented at the Tenth Congress of the International Society of Photogrammetry at Lisbon, Portugal, 
Sept. 7, 1964. The material in this paper has been cleared for open publication by the Department of 
Defense. Review of this material does not imply Department of Defense endorsement of factual accuracy 
or opinion. 
223