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INVESTIGATION OF REVISION TECHNIQUES FOR 
25K SCALED TOPOGRAPHIC MAPS 
O.A.AKABALI, E.UCAR, A.YILMAZ, O.AKSU 
General Command of Mapping, Photogrammetry Department, 06550 Dikimevi Ankara, Turkey - (aakabali, eucar, 
ayilmaz, oaksu)@hgk.mil.tr 
Commission VI, WG VI/4 
KEY WORDS: Topographic Maps, Stereo Plotters, Revision, Compilation, Digital Vector Data 
ABSTRACT: 
Revision of 25K topographic maps is one of the main duties of General Command of Mapping (GCM). Up to now, revision is 
carried out by stereo photogrammetric methods using 35K aerial photographs with different compilation systems (analogue and 
analytic stereo plotters, digital photogrammetric systems and analogue plotters with digital output). 
Due to technological developments and increasing amount of user requirements about digital vector data, it is vital to have a national 
geographic database of 25K maps in 2D and 3D. In the classical revision techniques with analogue and analytic stereo plotters; 
elevation, hydrographical and physiographical features were collected from the previous published maps and the other features were 
collected completely from the stereo model. But the data collected by this technique are not suitable for the digital vector database. 
For this reason classical revision techniques were abandoned. 
From the beginning of 2003, only digital photogrammetric systems have been used for map compilation purpose. Because of the 
superimposition capability of digital photogrammetric revision technique, elevation data are controlled from the digitized contour 
data file and the other features are collected completely. Thus, map revision period is increased. 
Turkey consists of approximately 5500 25K maps. Performing this task with stereo compilation method will take approximately 12 
years with the amount of digital photogrammetrie systems in Photogrammetry Department, GCM. This period is very long to meet 
the user demands. 
The aim of this project is to find an alternative map revision method, which is faster, but as effective and accurate as stereo methods. 
Four different compilation methods were examined by using two different scaled aerial photographs (25K, 35K). And two 25K 
topographic maps, which have different feature densities, were used in the project. Advantages and disadvantages of these methods 
and conclusions of the study are presented in this paper. 
I. INTRODUCTION From the beginning of 2003, only digital photogrammetric 
systems have been used for map compilation purpose. Because 
1.1 Purpose of The Project of the superimposition capability of digital photogrammetric 
e diras s revision technique, elevation data are controlled from the 
The investigation of alternative faster approaches to our digitized contour data file and the other features are collected 
revision. system in order to decrease the current map completely. Thus, map revision period is increased. 
compilation time was aimed in this project. But it must be as 
effective and accurate as the stereo methods. The revision period of a 25K topographic map with a 
) : : compilation operator takes 10 workdays (=80 hours) in 
1.2 Current Situation in Revision of Topographic Maps analogue, semi-analytical and digital systems from stereo 
models. The editing and control time of a 25K vector 
topographic map is 3 workdays (=24 Hours) and of a 25K 
classical topographic map is 8 (=64 hours). The resulting 
topographic map is handed in Topography Division for 
completion. 
The revision of 25K topographic maps is one of the main duties 
of General Command of Mapping (GCM). Turkey consists of 
approximately 5500 25K maps. Performing this task with stereo 
compilation method will take approximately 12 years with the 
current amount of digital photogrammetric systems in 
Photogrammetry Department, GCM. This period is very long to 2. COMPARISON OF COMPILATION METHODS 
meet the user demands. Up to now, revision is carried out by ; : 
stereo photogrammetric methods using 35K aerial photographs 2.1 Data Used for the Comparison 
with different compilation systems (analogue and analytic 
stereo plotters, digital photogrammetric systems and analogue 35K and 25K aerial photos (black and white) were used in the 
plotters with digital output). project. They were digitised in 21 micron resolution by a 
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