1409 
MAPPING FROM HIGH RESOLUTION DATA IN GIS SOFIA LTD. 
T. Madzharova, V. Petrova, K. Ivanova, M. Koeva, 
GIS SOFIA Ltd., 5 Serdika Str., BG-1000 Sofia, Bulgaria-photogrammetry@gis-sofia.bg 
Commission IV, WG IV-9 
KEY WORDS: Photogrammetry, Remote Sensing, Digital, GIS, Application, DEM/DTM, High Resolution, Visualization 
ABSTRACT: 
The high-resolution data have attracted much attention in photogrammetry and GIS. In the paper main approach for updating urban 
cadastral information using remote sensing and GIS data are described.The aerial photography over the part of the territory of Sofia 
Municipality is executed and the results after the adjustment are shown. An experiment in 4 variants was conducted to assess the 
accuracy of aerial triangulation that can be reached by means of digital photogrammetric system PHOTOMOD (Racurs Co., 
Moscow). The results show a reliable accuracy.High-resolution sattelite images from IKONOS and QuickBird taken during the years 
2000 to 2008 are used. The obtained products are orthophotomosaics (panchromatic and pan-sharpened), which are used for the aims 
of GIS SOFIA Ltd.. Orthophotoplans at 1:10000 scale for the mountain and 1:5000 for the plane regions on the territory of Sofia 
Municipality are produced. The results after the adjustment are shown in the table.In the concluding part of the paper image based 
presentations like satellite and aerial images are shown in the field of 3D visualization. Data collection and its various combinations 
are explained. The procedures for building and terrain modeling - alternative approaches for urban visualization are also described. 
1. INTRODUCTION 
Geographical Information System - Sofia Ltd. (GIS SOFIA), 
established in 1999, is a Sofia Municipality company. The main 
function of the company is to create and maintain the cadastral 
information system of Sofia Municipality, including cadastral 
maps at 1:1000 and 1:500 scale. The company is structured in 9 
departments. One of them is Photogrammetry Department, 
which main task is applying digital photogrammetry for 
building up and maintaining the cadastre. 
2. THE AERIAL PHOTOGRAPHY 
The aerial photography includes 405 colour pictures, covered 
around 98 sq. km - near the Vitosha and Balkan Mountains, 
taken by analogue aerial camera Zeiss RMK TOP 30/23 at 
1:5000 scale and scanned by DeltaScan with 12 pm pixel 
size. The project consists of two sub-projects: Vitosha Yaka 
and Balkan. 
2.1. Project characteristics 
Vitosha Yaka Project covers 86.80 sq.km area (217 cadastral 
sheets at 1:1000 scale, size 80x50 cm). The terrain is flat, 
lightly hilly and hilly not dense urban area with predominantly 
low houses. Average height of the terrain above sea level is 710 
m. The area is near Vitosha Mountain. 
Balkan Project covers 11.41 sq km area (28.5 cadastral sheets at 
1:1000 scale). The terrain is flat, lightly hilly and hilly not dense 
urban area with predominantly low houses. Average height of 
the terrain above sea level is 620 m. The area is near Balkan 
Mountain. 
2.2. Information sources 
The coordinates of pre-marked on the terrain ground control 
and check points are measured and determined by GPS- 
receiver Topcon GGD with an accuracy of ± 2 cm in 
position and ± 3 cm in height. 
The DTM, necessary for ortho-rectification, is generated 
from existing contours with interval 5 m. 
2.3. Producing the orthophoto-plan 
All ortophotoplans sheets at 1:1000 scale are made by digital 
photogrammetric system PHOTOMOD 4.2. The accuracy of the 
final product is shown by the mean square differences between 
geodetic and photogrammetric coordinates of the ground control 
points: In X - axis ± 3.7 cm; in Y - axis ± 3.4 cm; in XY - plane 
± 5.0 cm. 
PHOTOMOD is an up-to-date system using primary data from 
film or digital aerial cameras, as well as pushbroom CCD and 
radar spacebome sensors. The software package allows flexible 
workflow organization. It supplies user with the capabilities to 
perform the complete cycle of photogrammetric processing 
without engaging any third-party tools. 
3. THE EXPERIMENT - ACCURACY OF PHOTOMOD 
AERIAL TRIANGULATION 
For evaluation the capacity of a digital photogrammetric system 
of special importance is the accuracy of the aerial triangulation, 
performed by the system. For this reason an experiment in 
Photogrammetry Department was made. The aim of the 
experiment was to establish the accuracy of the aerial 
triangulation performed by the corresponding modules of the 
digital photogrammetric workstation PHOTOMOD. The 
experiment was conducted in 4 variants under same conditions, 
but with different quantitative parameters. A part of Vitosha 
Yaka Project is used as test area.