101 
USAGE OF AERIAL PHOTOGRAPHS 
Ivan Landek 1 , Stanislav Franges 2 
1 State Geodetic Administration 
Gruska 20, 10000 Zagreb, Croatia 
ivan.landek@dgu.tel.hr 
2 University of Zagreb, Faculty of Geodesy 
Kaciceva 26, 10000 Zagreb, Croatia 
sfranges@public.srce.hr 
KEYWORDS: aerial photography, cyclical survey, usage of aerial photographs 
ABSTRACT: 
Aerial photographs in digital form are applied except for geodetic purposes in some other branches of activity being the 
users of spatial data. Cyclical aerial photogrammetric survey of the Republic of Croatia is an extraordinary important 
project for space management. The paper emphasises the importance of digital aerial photographs for the purpose of 
local administration and self-government, especially for land register, spatial planning, demining and for other purposes 
where the visualisation of spatial databases is needed, e.g. in the work of economic, utility, tourist and other institutions. 
1. INTRODUCTION 
Photogrammetric survey is a surveying method using 
principally the photographs taken from the air. The results 
of photogrammetric survey can be the co-ordinates of 
single points, plans or some other graphic presentations 
and rectified photographs and the photomaps derived 
from them, photomosaics and panoramic photographs. 
According to the American society for Photogrammetry 
and Remote Sensing, photogrammetry is the art, science 
and technology of obtaining reliable information about the 
physical objects and environment by means of recording, 
measuring and interpreting the photographic images and 
electromagnetic radiation scenes obtained through sensor 
sistems. In the last twenty years, photogrammetry has 
been developing from analogous, through analytical to 
digital. During its historical development, photogrammetry 
has advanced into the sophisticated technology of 
surveying classical analogous photographs, and recently 
also into the survey of digital photographs. Exactly the 
survey of digital photographs and the possibilities of 
automated data gathering process makes digital 
photography be the optimal source of data for 
geoinformation systems. 
The present situation in photogrammetry and remote 
sensing denotes rapid development of: 
digital sensor techniques for obtaining the data; 
automation in data processing and photograph 
analysis; 
data management and analysis by applying CAD 
technology and geoinformation systems; 
data presentation with an emphasis on computer 
graphics, visualisation and animation. 
2. AERIAL PHOTOGRAPHS 
Aerial photography is a picture of a certain area. This 
pictures shows the entire contents in its shape and 
dimensions by means of tone differences, and by means 
of colour tones on colour photographs). Thus, the 
photographs contain a lot of information, and from the 
cartographic point of view, there is too many information 
to be presented on a map. On the other hand, the 
photograph does not have some important information 
being present on a map. These are titles, co-ordinate 
system and unique scale. Further, the photographs are 
made in central projection, and maps are made in various 
other projections. On single photographs, height image is 
rather weak and can be obtained indirectly (using shades, 
communication forms, form of parcels and the direction of 
their spreading, supporting walls, vegetation etc.), and the 
stereoscopic observation of photograph pairs give more 
reliable and clearer relief image. Hence, maps and 
photographs do not exclude each other in offering 
information, but they supplement each other which has 
led to the production of photomap (Lapaine and Francula, 
1998). 
Apart from analytical systems used now in 
photogrammetry, and photograph digitising with special 
scanners, digital systems will very soon be used in a 
much broader sense. The development of high-resolution 
sensors has helped digital systems to reach analytical 
system completely, referring to accuracy, and in some 
areas, they are already preferred, e.g. in digital relief 
models. Apart from that, their usage will enable the 
introduction of new technologies and the production of 
new products (Fiedler, 1998). 
Photogrammetric survey of classical analogous 
photographs in analytical form yields data in vector form. 
It has all the advantages and disadvantages of such an 
imagery. Vector form of data is convenient for vector 
oriented GIS. GISs are mostly developed with an aim to 
present and analyse the data as well as possible from the 
existing topographic maps. Vector model of points, lines 
and traverses in uninterrupted co-ordinate space allows 
the closest approximation of existing maps. But the 
structure of data is more complex than the raster structure 
and certain operations with vector data are more complex. 
Because of a large quantity of attributes per data unit, 
they make the vector model much more expensive. Unlike 
the vector oriented GIS, a large number of users are more 
familiar with the raster oriented GIS. The data for such 
systems are obtained mostly with sensors placed on 
satellites or aircraft. Raster data divide the surface into 
identically shaped unit image elements - pixels, saved as 
two-dimensional quantities in a computer, and each