books,
ists is
tion of
Inion of
through
iiety for
section
a and
national
iodically
ig from
es. The
normal-
vely 15
iss and
ed AN-
Gevaert
used.
on, etc.
satelites
space
sists of
25 000,
interval
of out-
| scales
ing the
m 1:10
1:5000
jastre.
f aerial
40 000.
e made
hs at
m 1:12
ing and
:500 is
3000 to
id 1:10
ales of
or rural
e made
sign of
various projects and structures such as motor-ways,
railways and other linear projects, bridges, tunnels and
other engineering structures, industrial and out-of-town
zones, etc. One should also mention photogrammetric
measuring of terrain profiles for automated design of
motor-ways and reconstruction of railway lines, as well as
photogrammetric inventory of existing road and railway
networks. Besides photomosaics at various scales are
made for the needs of townplanning. Revision is made of
geographic subject and small-scale topographic maps,
based on space photographs.
4.4. Aerial Triangulation
Analytical block aerial triangulation is widely used in
photogrammetric identification of the geodetic network.
The necessary measurement for this purpose are made
by means of the precise stereocomparators Stecometer
and Dicometer of Zeiss. Zeiss Transmark and Wild PUG-
4 devices are used for marking image points on the
diapositives. Computation is effected by means of
different computers, using Bulgarian or adapted
programs.
4.5. Apparatus
Stereoplotting is effected mainly by means of analog
instruments of the Zeiss Stereometrograph type, while
differential rectification is carried out by Topocart-
Orthophot and Topomat Zeiss systems. When
rectification is required it is most frequently carried out by
means of Zeiss SEG-5 and SEG-6 and Wild E-4
rectifiers.
Bulgarian made devices forming a system for graphic
data acquisition and processing are: Isot 9115E for
analog-digital data transformation, EC9002 and EC9004
data recording devices, Isot 230 alpha-numeric printer,
Isot 310 mini-computer and the Wild TA-2 Aviotab
automated plotter. The modules of this system are used
in different combinations for recording of photo-
grammetric measurements, digitalization of existing
urban maps, and for making digital models for various
purposes. Technologies for making and revision of urban
maps as well as for setting up cadastral information
system have been developed on the basis of the above
system. Scaners are in use also.
5.CLOSE-RANGE PHOTOGRAMMETRY
Terrestrial photogrammetry rendered measuring
processes in certain fields far more efficient. Among
these are construction, industry, mining, architecture,
archeology and road accidents.
For the purposes of architecture maps and photomaps of
Street areas, building facades, monuments and interior
design elements (iconostases, profiles and vaults of
churches, fragments, bas relief, murals, etc.)are made at
scales from 1:20 to 1:100. Terrestrial photogrammetry is
applied in industry to calculate volumes of bulk materials,
and for the needs of power generation construction to
9
plot underground areas intended for power stations. For
the needs of the hydrotechnical construction it is used for
digitalization of contours for estimation of changes in
water volumes of dams.
Terrestrial photogrammetry has been successfully
applied in tests of buildings and engineering structures as
well as in monitoring landslide areas. Photogrammetric
measurements are often used for determining areas and
volumes in open cast mining as well as terrestrial multi-
spectral photographs used for determining quality
parameters of coal. Terrestrial photogrammetric pictures
are taken by means of Zeiss and Wild universal metric
and stereometric cameras. Measurements are carried
out most frequently by Zeiss Technocart and other
suitable analog apparatus. When analytical methods are
applied measurements are carried out by precise stereo-
comparators.
6. THE PHOTOGRAMMETRY IN LAND
REFORM AND CADASTRE
The place of photogrammetry in the land reform and
cadastre in Bulgaria is determined mainly by six of its
multiple potentials:
(i) Use of retrospective aerial photographs taken over the
territory of Bulgaria for compilation of the topographic
map at 1:25 000 scale before pooling of private farms
into large collective farms. These aerial photographs are
taken by normal-angle aerial survey camera (focal length
21 cm, format 18x18 cm) and are at approximate scale of
1:20 000. In the prevailing cases real boundaries of
ownership at that time in mountain and hilly regions can
be distinguished on them, i.e. where presumably these
boundaries have been preserved up to now.
(ii) Production of large scale orthophotomaps without
contours as basis of the rural. cadastre. The
orthophotomap is cheaper and is produced considerably
faster than the conventional topographic map which
make it more up-to-date. The semantic information
contained on it is of the same quality and quantity as that
on the aerial photographs from which it is made.
(ii) Production and revision of very large-scale
topographic maps in graphical and digital forms as basis
of urban cadastre. This is a slower and more expensive
process but it is inevitable in view of its high precision
necessary for the compilation and updating of the
respective graphical and digital maps.
(iv) Production of photomosaics and other intermediate
photogrammetric products for the purposes of the land
reform. The photogrammetry has the advantage that
from the instant of taking the aerial photography up to the
production of the final product for which it is intended,
several intermediate products can be made with different
accuracy, serving some intermediate phases of the land
reform.
- (v) Determination of terrain points by aerial triangulation
for the needs of land reform and cadastre.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996
