3. CONCLUSION
Thus, an experimental working station
based on the suggested set of hardware
equipment and developed technological
software has been formed to accomplish
the whole complex of operations for
horizontal-vertical control network
bridging. The adjustment of blocks can be
done by using program package
"Photoblock" (TsNIIGAiK) and "Photocom"
(Sibgeoinform).
The efficiency of the technology is
defined by a number of factors. They are
as follows:
-an exclusion of artificial point
marking with all necessary expensive
instruments from the technological cycle;
- an increase of coordinate pointing
precision thanks to the use of digital
transfer and to high instrumental precision
of the analytical plotter being a basis of
the new technology;
- an automatization of processes of
project designing and stereoscopic
measurements, and control of the results
of major procedures.
The efficiency of the technology has been
proved, in addition to its efficient
theoretical solutions, by the results of
experimental studies carried out at
TsNIIGAIK on the STEREOANAGRAPH
AP by using photographs obtained from
1:5 000 aerial survey of the referenced
test area. For this purpose an aerial
camera with a view angle of 100 was
used. The choice of these test area
photographs attributed to the great number
of the targets on them determined on the
ground with an accuracy of 2 cm. So
the use of these aerial photographs has
provided reliable results of block
adjustment.
According to the developed technology
there has been adjusted a block consisted
442
of three strips, each of them having 7
photographs. RMS errors for the check
points at X, Y and Z coordinates from the
block adjustment by the "Photocom"
program are respectively 3, 3, 7 cm. It
allows compilation of a 1:500 scaled
topographic plan with contour intervals of
0.5 m for a flat relief, although due to
normative documents the scale of aerial
survey for a similar plan to be compiled
should be 1:3000.
Time-consumption records have been
taken during aerotriangulation procedures
based on the suggested technology with
automated point coordinate
measurements on "Stereoanagraph". The
time-study has shown that in comparison
with the technologies of artificial point
marking currently applied in mapping
production the new technology provides a
productivity increase in two times for
marking and measurement operations,
and - in 1.3 for the entire process of
aerotriangulation - from project designing
till final formation of a catalogue of the
adjusted coordinates. A preliminary
economical efficiency has been calculated
using the data obtained. For this purpose
some procedures and processes have
been taken into account, in particular,
aerial photography, geodetic bridging and
aerotriangulation for steretopographic
survey at scales of 1:5 000 - 1:500
with contour intervals of 1.0 and 0.5 m.
The developed technology of block
aerotriangulation on the STEREO-
ANAGRAPH analytical plotter leads to
scale reduction of surveys by 1.5 due to a
greater precision of block adjustment, as
well, as leads to a productivity increase,
and makes the routine work of an
operator much easier. All these factors,
as preliminary calculations have shown,
gain an annual economical effect of
about 50 million roubles per one working
station.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996