Crain, Ian 
  
4 SELECTION AND DEFINITION OF THE CORE DATASETS 
4.1 Approach 
The core datasets are those most likely to be required to support decision making for the identified common 
environmental issues. In determining these datasets consideration was given not only to the data needed to assess the 
state of the medium or phenomenon involved, but also of the root causes (or driving forces), and the potential impacts 
(or consequences). Towards this end, each of the common Subregional issues was elaborated in terms of driving forces, 
impacts, typical questions/decisions requiring core datasets, and the implied data requirements. 
This analysis was used to identify the scope and nature of the required data, and select those datasets considered to be 
“core”. 
1.2 Selection of the Core Dataset 
It is important to note, that the complete set of all data needed to address all aspects of an issue would be huge indeed, 
and not practical to collect or manage. The Core Datasets should include only those data which are fundamental or basic 
to providing information on the current state of the issue and related driving forces. In selecting data for inclusion in the 
core dataset particular emphasis has been placed on data which will support decision making for a number of issues. 
Some data are fundamental to nearly any environmental issue. These include the basic topography, climate, soil, land 
cover (including forest, grasslands and non-vegetative cover), the constructed infrastructure, and the administrative 
subdivision. These form the foundation upon which environmental decisions must be based. 
The resulting list of the SEMIS Core Datasets is as follows (Details in ADB, 1998a): 
Infrastructure Soil Class 
Vegetation Cover Air Quality Measurements 
Demography Climate Zonation 
Administrative Boundaries Topography 
Land Use Geology 
Major Harvesting Activities Water Quality Measurements 
5 STANDARDS ADOPTED 
5.1 Principles 
Exchanging environmental information requires standards for data exchange formats, but even more essential are means 
to ensure that the data can be effectively integrated and used. This requires data coding and content standards — 
particularly for the classification of thematic information layers, such as landuse, vegetation, soil and so on. For this 
reason, considerable effort was expended to adopt and adapt data standards suitable for the purpose, based on best 
international practice, adapted for the conditions of the GMS. There is insufficient space in this short paper to elaborate 
on the standards adopted. These have been described in detail in ADB, 1998b. 
6 CONCEPTUAL DATABASE DESIGN 
6.1 Design Criteria 
The following are the key criteria which have governed the development of the Conceptual Design of SEMIS: 
Decentralisation: The SEMIS design must provide for a decentralised network of databases which can link and 
exchange data within and between countries, as and when required. 
Hierarchical: A hierarchical system is required, in which detailed data will be kept nationally; integrated subregional 
data is managed by an agency in the subregion, with a potential for a higher level of integration held internationally. 
Spatially Based: All data are to be geo-referenced, so that decision makers can determine where a problem is 
occurring, as well as its extent and intensity. This implies a need for GIS functionality. 
Expandable/Flexible: Initially SEMIS addresses the needs to manage and exchange the Core Datasets. The design 
must also consider the need to easily add datasets in the future, and have flexibility to adjust to evolving needs. 
Ease of Use and Maintenance: The SEMIS design must provide for facilities for easy access to and management of 
data. There must be functions for the maintenance of "metadata" and other forms of auxiliary information. 
  
290 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.