DETERMINING AN INTERCHANGE STANDARD FOR THE NATIONAL SPATIAL DATA 
INFRASTRUCTURE OF TURKEY 
Çetin COMERT Gürol BANGER 
Karadeniz Technical University 
Department of Geodesy and Photogrammetry 
61080 Trabzon / TURKEY 
Commission II, Working Group 5 
KEYWORDS: Spatial, Data, Standards, Spatial Data Infrastructure, Spatial Data Interchange. 
ABSTRACT: 
Geographic Information Systems (GIS) have been receiving a growing interest from both public and private sectors in 
Turkey. Nevertheless, nationwide organizations dealing with spatial data have to have an effective way of sharing data 
to timely and economically meet ever evolving requirements. A National Spatial Data Infrastructure (NSDI) would 
greatly improve the accessibility, communication, and use of spatial data and enable nationwide data sharing. One of 
the most important technical requirements in building and maintaining the NSDI is a spatial data interchange standard. 
Due to the fact that designing a spatial data interchange standard is a colossal and long-term operation and acceptance 
as a "standard" in the end is not guaranteed, it would not be reasonable to design a new standard from scratch. Instead, a 
worldwide spatial data interchange standard could be adopted. To this end, a number of evaluation criteria which 
examine a spatial data interchange format in terms of its data model, implementation, and interchange environment 
have been determined. And DIGEST (Digital Geographic Information Exchange Standard), SAIF (Spatial Archive and 
Interchange Format), and SDTS (Spatial Data Transfer Standard) have been examined by the evaluation criteria. As the 
result of the evaluation, SAIF has been found to be the most appropriate. Identifying the need for NSDI in Turkey, this 
paper briefly presents the evaluation criteria and the evaluation. 
1. INTRODUCTION 
In spatial data handling, as well as other areas where 
Information Technology is employed, the need for 
computerized systems being "open", "integrated", 
"distributed", "interoperable", "corporate", "federated" 
have long been pronounced with some success, yet 
more to be achieved. The implications of these terms 
can be generalized as "distribution of tasks", "sharing 
of resources", and "cooperative processing" within 
and between systems. The deriving force behind all 
these has been to meet ever evolving requirements in 
an easy, fast, and cost-effective manner. Essentially 
meant with the "sharing of resources" here is the 
sharing of the software, hardware, and data. The 
particular interest of this paper is on the sharing of 
data. 
Often overlooked in the context of building and 
maintaining a Spatial Data Handling System is the 
timely provision of required data, which may cost 
much more than software and hardware together 
(Dickinson and Calkins, 1988; Frank, 1992). 
Collecting spatial data firsthand is a costly and time 
consuming operation no matter what particular method 
is employed. On the other hand, stimulated by ever 
increasing availability of digital spatial data, today's 
challenging applications require data with very 
different qualifications. The result is as phrased by 
Coleman and McLaughlin (1992):"..Information 
requirements for administration, resource management 
and environmental programs in countries around the 
world now outstrip the information collection 
capabilities of any single organization." 
Data sharing implies that the same digital data can be used 
by different users. Through data sharing, data collection 
costs can substantially be reduced since duplicate data 
collection activities of different organizations is avoided. 
Therefore, data sharing has been accepted as the way of 
providing timely and cost-effective solutions in spatial 
data handling (MSC, 1993; McLaughlin and Nichols, 
1994; Frank, 1992; Calkins, 1992). However, the success 
in the data sharing practices around the world has been 
rather limited (MSC, 1993; McLaughlin and Nichols, 
1994). Due to the technical and institutional problems 
involved, it has often been hard to obtain the required 
coordination and cooperation for data sharing. Therefore, 
the scopes of spatial data sharing programs have been 
limited to several agencies at the federal, state, or local 
levels (Coleman and McLaughlin, 1992). Institutional 
problems have been more difficult to overcome with 
respect to technical ones (Frank, 1992; Calkins, 1992; 
McLaughlin and Nichols, 1994; MSC, 1993). 
In this study, the need for a NSDI in Turkey is identified and 
a spatial data interchange standard which will be one of the 
most important components of the NSDI is proposed. Until 
a consensus is reached on the terminology, the term 
"spatial data" will be used in this paper to colletively refer 
to the data held in a Spatial Data Handling System (SDHS) 
which refers not only to GISs but also to other types of 
computerized systems dealing with spatial data. Also, the 
shorthand "IF" will be used for "spatial data interchange 
format". And the sides of an interchange will be refered to 
as "supplier" and "client". 
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996