METU, Faculty of Architecture, Department of Architecture, Inönü Blv., 06531 Ankara, Turkey - 
bilgin@arch.metu.edu.tr 
KEY WORDS: Multitemporal, Method, Decision Support, GIS, Heritage Information Management, Urban Conservation, Multi 
layered Towns, Bergama (Pergamon) 
Bergama is a multi-layered Anatolian town, which possesses the traces and material remains of different eras within its contemporary 
urban form. In order to sustain the multi-layered character of Bergama, the multitemporal spatial data concerning historical 
stratification should be considered as an integral part of conservation decision-making process. Hence, a decision supporting study, 
in which GIS is considered as the main tool, has been accomplished. In this paper, the main phases of the study are defined, together 
with the results provided through them. Considering the outcomes of the case of Bergama, the paper concludes with a discussion on 
the pros and cons of the GIS based assessment method in formation of a heritage information system to support the conservation 
decision-making process in multi-layered Anatolian towns. 
1. INTRODUCTION. 
Being subject to continuous inhabitancy beginning from early 
ages onwards, majority of the towns in Anatolia possess 
physical traces of different eras as different layers within their 
historical development processes, thus denoting them as multi 
layered towns. In multi-layered towns, it is the admixture of 
different layers and their relation with each other what 
contribute to urban identity through diversity and specificity. 
Hence, conservation and management studies should 
prominently consider their multi-layered character. 
Today, most of the multi-layered Anatolian towns are faced 
with the danger of losing their multi-layered character and 
resulting in one-dimensional areas. Along with many other 
causes, one of the main reason for this, is the incompatibility of 
conservation decisions and interventions with the physical 
structure and historical stratification of the town. 
Comprehensive, correct and utilizable information about 
historical stratification of the multi-layered town should support 
the conservation decision-making process so as to sustain the 
town’s multi-layered character. This calls for processing 
complex and huge amounts of data coming from various 
sources in various formats. 
Developments in information technology have been providing 
invaluable tools for handling complex and huge amounts of 
data, among which GIS have a special concern for dealing with 
spatial ones. GIS offer a medium compatible with multi 
dimensional dynamic nature of multi-layered towns and allow 
for the integration of various data concerning different layers of 
the town. 
In the view of these considerations, an information based 
assessment method has been built up for structuring, analysing 
and evaluating the multitemporal data about historical 
stratification as a decision support in multi-layered towns by 
using GIS*. In order to provide terminological, syntactic and 
structural standards, the elemental phases to be followed, 
terminology, format and means of providing, documenting and 
presenting data and system of rules in relating and questioning 
them are defined. 
Following is the implementation of this method on the case of 
Bergama (Pergamon), which is an outstanding representative of 
multi-layered Anatolian towns. 
ASSESSMENT OF HISTORICAL STRATIFICATION 
IN BERGAMA 
Bergama possesses a distinguishable multi-layered character as 
a result of continuous occupancy since early ages onwards. The 
inhabitation in and around the town is considered to be dating 
back to Prehistoric ages, although the earliest material remains 
which exist today belong to Geometric and Archaic Eras (Radt 
2002: 21-23). In the contemporary town of Bergama, it is 
possible to visualize traces and remains of Hellenistic, Roman, 
Principalities, Ottoman and Turkish Republican Eras as 
different layers constituting the urban form. 
Inspite of the multiplicity of layers belonging to different 
periods, the town is -unfortunately- faced with the danger of 
losing its multi-layered character in the near future. Major 
reason for this problem is the deficient consideration of the data 
concerning multi-layeredness in the urban conservation 
management and conservation decision-making processes. 
Being common to most of the multi-layered Anatolian towns, 
this problem has been studied through the case of Bergama as 
an important representative of such towns. 
The execution of the study required various softwares among 
which GIS played the major role. The basic softwares utilized 
are Adobe Photoshop 5.0, AutoCAD R14, and ArcViewGIS 
3.2. The major system properties of the PCs utilized during this 
* This study was carried on as a part of the Ph.D. Thesis of the 
author (Bilgin Altinoz 2003). 
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