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- What effort is needed to extract transferred 
information once being available in such a 
standard format, and without losing its meaning. 
- What tools the transfer should carry in order to 
support the retrieval and restructuring of the 
transferred data to the receiving system 
- What are the physical characteristics of the 
transfer media and format for information 
encoding (e.g. ISO 8211 Format). 
Various research groups had been formed in many 
countries since the 80th in order to handel these 
issues and design standards for the exchange of 
digital data. 
Several standards had been developed such as the 
Canadian CCSM National Standards for the Exchange 
of Digital Topographic Data, the USGS Digital Line 
Graphic Enhanced DLG-E, the UK National Transfer 
Format NTF, the USA Spatial Data Transfer 
Specification  SDTS, the Digital Geographic 
Information Exchange Standard DIGEST for Nato 
nations, [3], [8]. With few exceptions, the 
majority of these standards are in an experimental 
status (i.e. prototypes), subject to evaluation 
and enhancement. 
The International Cartographic Association ICA had 
founded the ICA working group on Digital 
Cartographic Database Exchange Standards with the 
objective to develop a mechanism for the exchange 
of experiences concerning such developments in 
many countries, [2], [3]. 
DEVELOPMENT PLAN 
Reference to the decision taken at Bakosurtanal in 
the frame of the next phase of the LREP project, 
1992-1996, the task of developing standards for 
the exchange of digital spatial data between the 
GIS Systems in the Information Network in 
Indonesia, is to be shared between Bakosurtanal 
and the BPPT (GIS and Remote Sensing Division, 
Ministry of Technology), where: 
- Bakosurtanal has the task to develop Standards 
for Data Exchange. 
This will include the design of the Information 
Model and its supporting Data Structure and the 
Transfer Format for the Data Exchange. 
- BPPT has the task to develop the ‘interfaces’ 
between this Standard and the various GIS 
Systems. This will include the development of 
procedures and computer packages for the 
conversion of data files in these systems to the 
Standard Format, and vice versa. 
The Bakosurtanal Working-Group on Specification, 
has the task to develop: 
- Standards for Data Transfer 
- Standards for Data Definition and Classification 
- Standards for Reporting on Data Quality 
- Data Dictionary 
Due to the complexity of such a task and the time 
and manpower needed for its completion, and the 
lack of information about the systems to be 
considered, we proceeded with this task as 
follows: 
- Study and analysis of the available documents 
about the specifications made by many mapping 
institutions around the world, as listed in [8]. 
- Based on this study and reference to our 
previous work on the design of concepts for the 
Bakosurtanal  Topographic Databases, [5], the 
first draft (a prototype) on standard was 
produced in 1991 under the name: 
BAKO DATA EXCHANGE FORMAT. This work involves 
the definition of data types, the transfer’s 
data model for the modelling of terrain 
features, the data structure which support this 
233 
model and the format for data organization (i.e. 
data records). 
- Empirical testing on this prototype and the 
following versions has be completed before 
submission for designation as a National 
Standard for Data Exchange. 
In this test, encoded data files, extracted from 
the Bakosurtanal Database, will be exchange and 
decoded by the participating agencies. The 
concepts of the transfer will be evaluated and 
suggestions for enhancement and adaptation to 
the Indonesian environment will be considered in 
the next version. 
- At this phase of development, only the transfer 
of vector data is considered. Raster data will 
also be considered in later stage. 
TRANSFER STRUCTURE IN THE 
BAKO DATA EXCHANGE FORMAT 
The main feature of the Bakosurtanal Standard is 
the use of of the ’Object-Oriented’ concept in 
modelling terrain features as a base for the 
transfer of terrain information. This concept is 
consistent with the logic of the user’s view on 
the real world as a sets of objects of different 
semantic classes and of different levels of 
complexity. This is contrary to the conventional 
approach which is 'map-sheet/ oriented and based 
on the use of the basic map elements 
(point/line/area), classified in themes, for the 
modelling of terrain information. 
In most of the published Standards, vith fev 
exceptions, the object to map element relation is 
1:1 relation, i.e. the object is either a point, a 
line or an area. In our approach, this relation is 
n:m relation, i.e. one object in the transfer, 
will refer to other objects of less complexity 
and/or more than one map element for its spatial 
description. Similarly, one map element could be 
shared by more objects, in the same or different 
sematic classes in the data hierarchy. 
Further, the semantic attributes are defined and 
assigned to the object, rather than to the basic 
map elements. These elements however, will have a 
set of ‘standard’ attributes: reference to classes 
which it belongs, and information about source, 
method and quality of its extraction. 
Terrain information and other supporting 
information being transferred at any one time is 
called ‘TRANSFER’ which might occupy one or more 
physical volumes. 
Logically, the Transfer in this Standard Format 
will consist of several (related) data types: 
- Data Area-Tiles: each consists of geographically 
related collection of Data Theme-Groups 
- Data Theme-Groups: each consists of 
topologically and geographically related 
collection of Data Themes (Entity Classes) 
- Data Themes (Entity Classes): each consists of a 
collection of thematically related Entity-Types 
(Subclasses). 
- Data  Entity-Type: a collection of terrain 
features (objects). These objects are described 
by its spatial (location and geometry) and 
semantic (attributes) descriptors and the 
relationships between them. 
- Objects: objects included in the Transfer can be 
at various levels of complexity, where complex 
objects are composed of objects of lower logical 
level in the data hierarchy. In the lowest 
level, objects are sets of primitive map 
elements (points, lines, areas). 
The composition of a complex object is described 
by a set of indices to the data records of the