factors 29 different variants have been evaluated (figure 1 shows
an example).
In order to solve the pending problems at the Federal Office of
Standards and Surveying in Vienna, especially with regard to con-
tour line evaluation in the 1:5 000 and 1:10 000 scales SCOP was
tentatively installed at the IBM 370/158 of the Federal Office.
1.2 Further Development
Especially when evaluating scales larger than 1:5 000, which is
necessary for preliminary and final design, an expansion of the
program becomes necessary in the direction of a preferential
treatment of the break lines. The program expanded by the break
lines (SCOP-B) first produces a DHM which contains both the
heights of a regular grid and the heights of the intersection
points of the break lines with the grid lines. In the second
part of the program the contour lines are interpolated, atten-
tion being paid to the break lines in the DHM, and prepared cor-
respondingly for the automatic plotter. Figure 2 shows an example
of the road administration of the state of Lower Saxony (Federal
Republic of Germany), giving a good idea how the contours make
angles at the break lines. The initial data were about 400 ter-
restrially recorded terrain points.
Further details of this development may be studied in a paper
presented by'E ASSMUS /1/, Institute of Photogrammetry of Vienna
Technical University.
2. DIGITALLY CONTROLLED ORTHOPHOTO PRODUCTION
The Wild Company will present their digitally controlled orthopro-
jector Avioplan ORI] on the occasion of the congress at Helsinki
/10/ /8/. The Institute of Photogrammetry of Vienna Technical Uni-
versity signed a development contract with the Wild Company in or-
der to prepare the software for the off-line operation. The entire
program package requires a core memory of 128K bytes and is called
SORA (Software for the off-line rectification by Avioplan).
2.1 SORA-0P for the Production of Orthophotos
Data acquisition is done by analog plotting instrument to which 3
coordinate-recording system with magnetic tape unit is attached!).
Data acquisition can be done on the basis of absolute orientation
in the form of contour lines or on the basis of relative orienta-
tion in the form of profiles. Furthermore, the terrain points may
be distributed irregularly, so that also very accurate orthophotos
can be made from urban and forest areas.
In principle the initial data may also be gained by digitising the
contours of already existing line maps.
DEor our test examples the Federal Office of Standards and Sur-
veying in Vienna has undertaken data-acquisition on a Wild A7
with EK22 and magnetic tape unit.
