INTEGRATED GEOGRAPHICAL BUFFERING SYSTEM FOR LAND TAXATION IN 
SRI LANKA 
Ravindra S. Thilakarathne 3 , Jagath Gunatilake b , JAS Jayakody 3 
a Faculty of Geomatics, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya, Sri Lanka - 
(ravin, swama)@sab.ac.lk, http://www.sab.ac.lk 
b Postgraduate Institute of Science, University of Peradeniya, Peradeniya, Sri Lanka - 
jagath@pgis.ac.lk , http://www.pgis.ac.lk 
KEY WORDS: Land, GIS, Database, Satellite, Imagery 
ABSTRACT 
Land property has value because it provides amenities and satisfactions of living, as in the case of residences and services, while 
property taxes are essentially concerned with improvements to the land. The methods used for land value taxation are varied and 
seem quite complicated in most developing countries. And most of the issues associated with land taxation in developing countries 
are also relevant to Sri Lanka. It has been financially costly, since there is no systematic and easily updateable land property rating 
system covering the entire country which gives descriptions and records of land values functional to socio-economic and 
infrastructural changes with the rapid growth of population in Sri Lanka and the existing various land valuation records are disparate, 
incomplete and very much out of date.Integrated Geographical Buffering System (IGBS) is an alternative solution for land valuation, 
hence to retain as a graphical database for land taxation over georeferenced and georectified high resolution satellite background 
imagery through a computer environment to identify and map all land properties, classify, analyze market data, value its price in 
relation to streets and other facilities, identify owners and tax payers and finally to simplify and improve proper land taxation roles 
through the use of better techniques for the effective development of the country. 
1. INTRODUCTION 
Land valuation is the art and science of assessing the value of 
land property. The value of a land property is determined by 
demand and supply of the land property in the market. The land 
parcel value mainly depends on its location while a number of 
physical and socio-economic characteristics are intrinsic to the 
land. The landowner is liable to pay the rates unless exempted 
by local governments, even very low income groups. A wide 
verity of land tax layouts are already being used in developing 
countries. In Sri Lanka there are several taxes imposed by the 
central government which have a bearing on land and the 
valuation process is traditionally accounted by the valuers’ 
expert knowledge of a locality. 
The process of valuation may be described as the carefully 
considered estimate of worth of landed property based on 
experience and judgment by identifying and assessing the 
characteristics of a given land. The purpose of valuation is, 
however, to determine “value”, a term generally prefaced by 
some description such as market value or benefit value. In 
general, lack of information, funds, shortage of technical and 
administrative personnel delay implementation of the needed 
large scale land valuation activities. However, the determination 
of a land parcel value depends on a number of physical and 
economic characteristics which must be taken into consideration 
very carefully in a land valuation procedure. Some of these 
characteristics are intrinsic to the land; others are external or 
environmental factors. These factors can be determined in an 
objective way but there is always a certain degree of 
subjectivity that is difficult to measure in the valuation process 
[6]. 
Locational influences on property value are widely regarded as 
the most important, yet their incorporation into valuation 
methodology is often implicit. GIS-based value maps are 
introduced as a means of displaying variations in value at the 
individual property level. There are many property market 
characteristics that make valuation a difficult and often 
subjective task that is dependent on a high degree of experience 
and local knowledge, for example the heterogeneity of each 
interest, economic influences at the national, regional and local 
scales. These characteristics cannot be altered and indeed make 
valuation a challenging profession. However, it would be seem 
prudent to minimize valuation a complexity by improving data 
accessibility and dissemination [4]. 
2. EXISTING LAND VALUATION METHODS 
The use of a particular property valuation technique is 
dependent on property type and the purpose of the valuation [3]. 
2.1 Comparative Method 
This method assumes that the market value is equal to the price 
recently paid for a similar property or interested in land. The 
valuer’s problem is to determine what the market considers to 
be recent and similar. Adjustments may need to be made for 
differences between the properties used in the comparison and 
changes that have subsequently taken place in the market or are 
of a structural nature. If an almost identical house were recently 
sold next door for a known price but which lacked a particular 
facility such as a garage or central heating, then slightly 
different assessment would be expected. The approach is often 
the most simple and efficient means of determining market 
value, especially for single-family residential properties in an 
active market. 
2.2 Income Method 
This method is also a comparative method and holds that the 
market value of an interest in land is equal to the present value 
of the net income that should in future come from the land. The