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MEANS AND METHODS IN AUTOMATED PHOTOGRAMMETRY 
  
Report from Sweden 
  
Sven G. MÖLLER, Stockholm 
1.- The National Land Survey Board studied ''100 meter photogrammetry for forestry'. The Wild 
Digimeter for orthogonal coordinates was used as à monocomparator. In order to increase accu- 
racy a mirror stereoscope with stereomicrometer was used instead of the standard microscope. 
Two aerial photographs, if necessary enlarged 4 times, could be observed in stereo as one model 
and be measured separately. 
  
A program for analytical photogrammetry had been compiled by Mr C, U, Thorsell, based 
upon ideas given by Prof, Karl Rinner, Austria, and Prof, E.H. Thompson, England. The Digi- 
meter and the program were checked, using a Swedish testfield on Óland and aerial photographs 
taken with Wild Aviogon 15/23 from 2 200 meters (negative scale 1:15 000). The standard error 
of unit weight from the numerical adjustment of absolute orientation on 20 points with known geo- 
detic coordinates was 123 mm. The maximum difference between photogrammetric.and geodetic 
coordinates for the same points were 133 mm in x, 242 mm in y and 266 mm in z, 
The program was compiled in such a way, that coordinates photogrammetrically measured 
in a Wild A7 or a mono- or stereocomparator, could be handled, 
Another program had originally been compiled in order to calculate and adjust coordinates 
measured geodetically, but also to construct plans at a scale of 1:400, 1:1 000, 1:2 000 etc... 
and to draw them, The computer used was GIER from AS Regnecentralen in Denmark, The flatbed 
plotter Kingmatic 215 from Norway was used in combination with the steering unite RC 1600 from 
Denmark, All curves had to be drawn as series of short lines, Notwithstanding subprograms were 
compiled for the drawing of letters and figures, The production of large scale plans is about 
14 000 plots with 78 000 points a year, coming out from one plotter. 
Analytical photogrammetry with its program had in a few cases been combined with the 
equipment and program for the compiling and drawing of plans, 
Semantic information about landscape can obviously be coded in figures. This information 
could be interpreted in the aerial photographs or assembled in the field and be transferred over 
a Digimeter, comparator or a coordinate registration equipment to a tape, but also further on to 
the plan, where it could be drawn as a code or a symbol in the right position on the plan, 
2, - The Central Board for Real Estate Data is experimenting with the Digimeter and the program 
for the compiling and drawing of plans in order to bring land register plans over from an old plan 
division system to a new standardized system, At the same time plan details are being revised 
and completed, 
  
That is only one small part of the work with the new Land Data Bank of Sweden, repor- 
ted of earlier, From 1971 this Board was organized in order to develop the system not only for 
the Land Register but also for many other registers about landscape and its inhabitants, Automa- 
tic data processing, automatic drawing of plans, transferring and presentation of such data will 
be included in the system. 
3.- The Geographical Survey Office presented a study "Experimental Topographic Map Drafting 
Using Numerically Controlled Methods" by Lars Ottoson. Meddelande Nr D 13 1971. 
  
D-Mac pencil follower was used for digitizing, point by point for point symbols and 
straight lines, but with time intervals for irregular map elements. Map size 50 x 50 cm. 
Univac 1108 and Fortran were used, The program had to consider the transformation 
of data to common systems and accuracy, to identify colour separation sheets and map symbols, 
to state tool positions and delete erroneous data etc, The proper tape contained about 187 000 
signs, The cost for the computer work was about US $ 140. 
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