AN ATTEMPT TO AUTOMATED GENERALIZATION OF BUILDINGS AND 
SETTLEMENT AREAS IN TOPOGRAPHIC MAPS 
M. Basaraner * and M. Selcuk 
Yildiz Technical University (YTU), Department of Geodetic and Photogrammetric Engineering, 
34349 Besiktas Istanbul, Turkey - (mbasaran, selcuk)@yildiz.edu.tr 
Commission IV, WG IV/3 
KEY WORDS: Cartography, GIS, Generalization, Object, Database, Scale, Analysis, Processing. 
ABSTRACT: 
Generalization of topographic maps is a very challenging problem for map producers. Therefore, NMAs are intensively working on 
the matter in order to make it automated as much as possible for their production requirements. In this paper, we present a case study 
for automated generalization of buildings and settlement areas in Turkish topographic maps from 1:25K to 1:50K, which is 
implemented in Laser-Scan LAMPS2 GIS and map production software based on object-oriented database technology. It begins with 
the issues regarded in their generalization. Then, steps for generalization of surrounding roads of settlement areas are mentioned in a 
limited focus. After that comprehensive steps for generalization of buildings and settlement areas are given. At the beginning, 
settlement areas were stored as a whole without any direct interaction with roads. Their independent generalization created some 
problems and we did not have the possibility of analysing the areas surrounded by roads for the decisions in some building 
generalization operations. To solve these problems, we create settlement blocks using road segments after creating buffers on roads 
considering symbology and then partition existing settlement arcas according to these blocks. After that voronoi diagrams are created 
and combined according to building clusters. It enabled us to analyse within the blocks for optimal generalization decisions. First 
results of this ongoing study are close to solution although some editing is required. It concludes with an evaluation of results, 
addressing future work. 
1. INTRODUCTION 2. CARTOGRAPHIC GENERALIZATION OF 
BUILDINGS AND SETTLEMENT AREAS 
Maps at various scales and types are needed in different 
fields such as urban and regional planning, geosciences, Cartographic generalization is responsible for reducing 
transportation, natural resource management, environmental complexity in a map in a scale reduction process, 
protection, defense, tourism, statistics, education, etc. emphasizing the essential while suppressing the unimportant, 
Cartographic generalization is used for this purpose and maintaining logical and unambiguous relations between map 
despite intensive research for last 30 years, a completely objects, and preserving aesthetic quality. The main objective 
satisfying solution could not be found. Among main reasons then is to create maps of high graphical clarity, so that the 
are initiative component of map design (Weibel, 1995; map image can easily perceived and the message the map 
Spiess, 1995), and necessity of more advanced techniques for intends to deliver can be readily understood. Scale reduction 
spatial data modeling (Ruas, 1998; Ormsby and Mackaness, from a source map to a target map leads to a compctition for 
1999; Weibel and Dutton, 1999), analysis (Ruas, 1998b), space among map features caused by two cumulative effects: 
interpretation/mining (Sester, 2000; Anders and Sester, 2000) at a reduced scale, less space is available on the map to place 
and processing (Weibel, 1997). symbols representing map features, while at the same time, 
symbol size increases relative to the ground it covers in order 
Cartographic generalization has been made by experienced to maintain size relations and legibility. These can be 
cartographers in many NMAs until today. However, the resolved by simplifying symbolism, by selecting only a 
requirement of building one master database and deriving subset of features to depict, and by displacing some features 
other lower LoDs or smaller scales from this database mainly away from others (Weibel and Dutton, 1999). 
due to economical reasons; data updating and map revision 
problems especially in large countries; national, regional and Buildings and settlement areas are among dominant object 
global SDI activities; intensive demands of society for types in topographic maps. Building generalization is an 
geospatial data and digital maps together with increasingly important step in the generalization process for maps at 
widespreading use of GIS, web maps and map-based mobile medium scales (until 1:100K). Modifications of shape and 
guides make it essential to automate generalization. modification of location are led by geometric, topological 
and gestalt constraints as design considerations. Whilst the 
Regarding these requirements and developments, Turkish shapes of buildings are usually the most affected by 
NMA, GCM, has started a project to obtain 1:100K maps generalization (changed into rectangle or square in the best 
from base topographic maps at scale 1:25K and later 1:50K case, typified, removed, aggregated or amalgamated 
will be dealt with. In this paper, we will present a case study otherwise), it appears that for topographic maps (1:25K and 
for cartographic generalization of buildings and settlement 1:50K), discriminative characteristics of each particular 
areas from 1:25K to 1:50K, aiming at supporting the ongoing buildings are retained as much as possible (Regnauld et al., 
studies of generalization and national SDI in Turkey. 1999), Buildings are enlarged according to visual graphic 
resolution thresholds to be visible at target scale and their 
relative sizes are tried to be preserved. 
  
* Corresponding author. 
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