[This document is also available as PDF file (approx. 20Kb)]
1. Background With rapid economic growth and the marked decrease in the hardware and software price of GIS, there is increasingly great demand for GIS in Asia and the Pacific. One of the main bottlenecks in GIS development in the area comes from the lacking of fundamental spatial data sets or its availability. In particular, regional fundamental spatial data sets of Asia and the Pacific is still missing since many countries in the area have different institutional framework and technical standards. In fact, the fundamental spatial data sets and its data sharing policy might be very different from that in Malaysia and India.
In order to promote GIS development in Asia and the Pacific, PCGIAP proposed to develop and implement the Asia-Pacific Spatial Data Infrastructure (APSDI). APSDI is a network of databases, located throughout the Asian Pacific Region, that together provide the fundamental data needed to achieve the region's economic, social, human resources development and environment objectives.
From the technical point of view, such an APSDI is composed by a network of APSDI clearinghouse nodes. These data nodes will make the existing data sets discoverable and enable ready access to data for regional applications. In other words, the data nodes will provide means to advertise data collection, requirements, inventory, and quality; support documentation of basic spatial data sets. In addition, these data nodes will minimize duplication of effort in fundamental spatial data collection and processing in the area
2. Architecture and functions of APSDI nodes
2.1 Architecture of an APSDI node
The role of an APSDI Data Node is to manage, maintain and distribute fundamental data. It can include Web servers, metadata or data dictionary and fundamental data sets.
The webservers can be established institutionally or geographically to optimize sharing of common computer resources.
Metadata is one of the most important components of the node. Its role is not only to help organize internal investment in spatial data, but also to provide inventory and quality information to catalog and brokers; to provide information to process and interpret data received in data transfer. From the use point of view, the metadata serves as a data directory which shows the visitors how/what about the data. For example, how to use the data, what does the data mean and so forth.
Since the precision or scale of spatial information used for national or local applications may not be necessary for regional applications, the fundamental data sets of each APSDI node would be generalized and integrated based on the national data sets. The original national data sets need to be transformed into APSDI data according to the technical standards of APSDI. In addition to the digital data, the catalog information about the analog data (such as paper maps, CD-ROM, Tape stored data and so on ) need to be included in the data dictionary of the data nodes.
From the technical point of view, an APSDI node consists of> Network interface, Metadata, Fundamental database, Data distribute rules and Data distribution tools. Both hardware and software need network interface to communicate with other APSDI Data Nodes. Software interface means an open communication protocol. Hardware interface means the ability of connecting the Internet physically. Data distribution tools include WWW, FTP, Email server softwares etc. Data distribute rules include management rules, data share rules and security rules.
2.2 Functions of APSDI nodes
An APSDI node should have following functions::
To access the distributed data securely, sometimes the visitor needs an authorized identification.
Give the visitor an entrance and guideline to the distributed data or any data products.
Visitor may query the WWW station of a data node to get some information or some fundamental data, and then check the result in the browser. For instance, the data node may tell the user what kind of data is available according to the visitor's query condition, even show the visitor the original data in the browser as he wants.
Every data node should be a fundamental clearinghouse for that region, here users can download some qualified free data, also can upload any qualified data just for exchange.
Visitors can author a map using the fundamental data at data node on-line. So users from any corner in the world can take use of the data without downloading it.
The APSDI Data Node should distribute not only the fundamental data, but also some on-line services about the data, for example, route analysis, 3D visualization and so on.
2.3. Networking APSDI nodes
APSDI Network is a network of APSDI data nodes throughout the region, which is constructed by using common technical standards (TCP/IP, WWW, metadata standards, Spatial data format for exchange, etc), compatible administrative rules (user registry, authorization), and commonly agreed data sharing policies (pricing, secret/decipher/encrypt, data update etc.) Technically, an APSDI Network may be demonstrated by following picture. To implement this network, the data nodes must be developed at first.
3. Actions to be taken
3.1 Prototyping data nodes
Two or four data nodes need to be identified within member countries. Each data node should be a key institution of the nation or region who has the expertise and resources to set up and maintain a data node. Australia, China, Iran and Japan would be the list of candidates.
For each data node, a GIS clearinghouse need to be established with web servers, metadata, data dictionary and fundamental data sets. Any other users should have an easy access to the node. These nodes could serve as demonstrations systems for other member nations.
3.2 Documentation and training
Based on the development and testing of these proptotype nodes, the architecture and functions of the nodes and its relevant specifications could be formulated.
One or several training courses should be organised for transferring the knowledge and technology on establishing an APSDI node to other member counties, especially those from developing countries. Efforts need to be devoted for getting the financial support from ESCAP and other international organisations.
3.3 Setting up and networking the APSDI nodes
The final number of data nodes will have to be determined by all members.
The directory of APSDI data nodes and details of access to data will be published.
4. Some of the questions to be discussed
The contact point for this web page is GlennJohnstone@auslig.gov.au
Copyright (C) PCGIAP
This page was last updated 01-06-1999.