The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
The mean square differences between geodetic and 
photogrammetric coordinates of the check points on the terrain 
in different variants are in the following range: 
In X-axis: ± 4.5 to ± 7.3 cm, in Y-axis: ± 4.3 to ± 9.3 cm, in 
XY-plane: ± 6.3 to ± 11.8 cm, in Z-axis: ± 8.0 to ± 26.7 cm. 
General information about the experiment project: 
Blocs of aerial pictures 1 
Strips of aerial pictures 6 
Aerial pictures 14+17+18+18+19+19 = 105 
Approximate picture scale 1:4710 
Average flight height above the terrain, m 1440 
Ground pixel size, cm 5.7 
Pre-marked points on the terrain 36 
Pictures per 1 pre-marked point 3 
Tie points 786 
4. THE SATELLITES IMAGERY 
4.1. QuickBird sattelite project 
Pan-sharpened QuickBird Standard Ortho-ready sattelte images, 
dated August-September 2007 and March-April 2008, covered 
the whole territory of Sofia Municipality (1341.8 sq. km). They 
are user for production of orthophotoplans at 1:10 000 scale for 
the mountain and 1:5000 for the plane regions on the territory. 
Because of the nature of activity of GIS SOFIA Ltd. sufficient 
number of geodetically determined points is provided. Specific 
elements from the terrain, which are clearly visible on the 
images and defined at earlier geodetic surveys, are used. 
Orthorectification by use of DEM generate from contours at 5 m 
is performed. The obtained RMS error in position of 59 ground 
control points is ± 1.31 m. 
4.2. IKONOS sattelite project 
Fifteen panchromatic and fifteen multispectral images from 
IKONOS, dated June 2005, over the whole territory of Sofia 
Municipality are processed. 
The obtained products are 2 mosaics (panchromatic and pan- 
sharpened), which are used for the aims of GIS SOFIA. 
Orthophotoplans at 1:10 000 scale for the mountain and 1:5000 
for the plane regions on the territory of Sofia Municipality are 
made. The results after the adjustment are shown in the table 1. 
Points: 
Control 
Check 
Tie 
Number 
95 
75 
, 301 
RMS in X, m 
±0.70 
± 1.47 
±0.13 
RMS in Y, m 
±0.65 
± 1.30 
±0.14 
RMS in XY, m 
±0.99 
± 1.99 
±0.21 
Table 1. Ground control and check points residuals 
4.3. Establishing changes on the Territory 
Three panchromatic and three multispectral images from 
IKONOS, dated 04.09.2000, 11.07.2000 and 03.07.2002 
covered a part of Vitosha Mountain Park are processed. 
To establish changes on the territory of Vitosha Mountain Park 
satellite images from IKONOS are used. Orthorectified product 
covers 220 sq. km and was used for the change detection of the 
forest territory. The accuracy, obtained for the check points on 
XY - plane is ± 4.96 m. 
4.4. Updating of topographic map at 1:5000 scale 
For the highly intensive activity regions of Bulgaria the large 
scale topographic map is produced at 1:5000 scale and for the 
less intensive ones - high mountain and forest regions - at 
1:10000 scale. 
The large scale topographic maps for the territory of Bulgaria 
have been produced in “1970” co-ordinate system and Baltic 
elevation system. Each map sheet with dimensions 50 x 50 cm 
in the scale of the map covers 2.50 x 2.50 km = 6.25 km 2 from 
the Earth’s surface. 
The large-scale topographic map is subject to periodic revision 
depending on the respective needs. Due to the rapid change of 
the Capital Sofia infrastructure, it was necessary to revise the 
topographic map at scale of 1:5000 for a part of the city. 
Main source of information for revision of the map was the 
orthorectified QickBird satellite image. 
Basic data about the selected image 
The used image is panchromatic, Basic Imagery, which covers 
the central part of Sofia. It is an archive image, taken on 27 
March 2003 at 09:17 hours GMT. The period, when the image 
is made, is very appropriate in view of vegetation of plants - 
nearly no leafs, which could stand in the way of important 
features. Although the early spring is characterized with an 
unstable weather conditions, in this case they are extremely 
appropriate - 0 % clouds. The time interval between acquisition 
of the image and the time of its purchase and start of further 
processing for orthorectification and deriving the vector 
information is within a period four months, which is completely 
satisfactory. 
Use of Rational Polynomial Coefficients (RPC), supplied by 
QuickBird, with further polynomial transformations 
The following approach is used: 
V Transformation by use of the RPC is made. 
X The precision of the obtained result is increased by means 
of 3D polynomial transformations of the basis of points, 
measured by GPS. 
For the experiment 8 control and 15 check points, normally 
distributed within the range of the image, are used. The 
obtained maximum and RMS errors in location in the check 
points are 2.56 and ± 1.40 m. 
The analysis of results shows that this approach ensures needed 
accuracy for scale 1:5000 in the range of the entire image. 
When object boundaries are unclear and can not be identified 
properly, other sources of information are used: 
V Data from the cadastral information. 
V Field interpretation of the image. 
V Field survey. 
5. PROJECT IN THE FUTURE 
Hansa Luftbild has flown over a territory of 1467.1 sq. km area. 
The pictures are taken by digital aerial camera DMC. For the 
urban area of 811.3 sq. km, GSD 10 cm, forward overlap 80%,