Pergamon Comput., Environ. and Urban Systems, Vol. 19, No. 3, pp. 179-184, 1995

Copyright © 1995 Elsevier Science Ltd. Printed in the USA. All rights reserved

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EDI BASED GEOGRAPHIC INFORMATION SERVICE a

Antti Rainio Geographic Information Centre, National Land Survey, Helsinki, Finland

ABSTRACT. EDI (Electronic Data Interchange) based geographic information service is a general client~server approach enabling automatic information service to end user appfications. It is based on international standards and can be implemented with general EDI software tools. All important geographic data resources will be available for the applications which are able to send an electronic order through a data network and in real-time receive the response data sent by the data supplier's server system. EDI based information service is designed, piloted, standardised and implementedin Finland. Many o f the national data suppliers are active and the service already covers ten databases. The Geographic Information Centre at the National Land Survey is maintaining a geographic data directory system and supporting the implementation o f services and end user applications by consulting and by developing software supporting the standards.

BACKGROUND INFORMATION

In 1985 in Finland, development projects for the joint use of geographic information were launched by the Ministry of Agriculture and Forestry. More than one hundred people took part in eight working groups preparing standards and facilities of an EDI based geographic information service. After several versions and pilot schemes the service is now available for users in Finland. The Geographic Information Centre at the National Land Survey has its roots in the secretarial and piloting work during the project. It is now, as a service centre, activating the development of the joint use of geographic information. Data suppliers and software houses work in cooperation in order to satisfy the needs of end users.

CHARACTERISTICS

The components of the EDI based geographic information service are data suppliers information systems, user applications, a data network and a geographic data directory system. These components interoperate and act like a logical system.

As a benefit of the service, users do not need to copy existing databases and update copies. Instead, end user applications send electronic orders: i.e., query messages through a data network for any piece of data. Requested data is immediately sent as a response message to a user application.

A database becomes a part of the EDI based geographic information service when the server interface is implemented. The target is to include all important geographic data re-

a This paper also appears in the proceedings of the 17th Urban Data Management Symposium (UDMS) '94, held in Helsinki-Expoo on September 4-8, 1994.

179

180

Directory data

A. Rainio

I I I j ).-

Cad~

Builq

ata

lata

Enterprise data [ ~ [ ~ Environmental data

Population data Natural resource data

FIGURE 1. EDI Based Geographic Information Service. All Geographic Data Resources Will be Available for End User Applications Through EDI Based Information Service. In Finland the Service Interface has Already been Implemented for the Most Important National Databases Covering Data about Real Estates, Buildings, Persons, Roads, Environment Quality, etc. (Enterprises, Weather, etc. are Under Preparation).

sources in the service. This means perhaps a hundred of databases from several organisa- tions at the state or local level (Figure 1).

The EDI based geographic information service is an open client/server concept which is based on international EDI standards, especially EDIFACT (ISO 9735). It is application- to-application data interchange where the server systems of geographic data suppliers are serving the client applications of end users. The both ends of the interchange are supported by EDI software including an EDI translator. Even if the interchange is batch processing, the response can be sent in real-time. The orders are handled immediately or with delay: i.e., "just-on-time".

Advantages to Data Suppliers

A geographic data supplier will save resources most of all by having the EDI based infor- mation service fully automated. The same implementation is serving all different applica- tions in real-time or with delay. As the user interfaces are running on the computers of end users, the service system is not so loaded. As the service is a batch process, the number of needed user licencies is very small. The data network is loaded only during transportation which means lower costs for connection to a data network. Data security is better because outsiders do not have sessions at the service system.

Advantages to Users The EDI based information service make the data resources available to users whatever

tools and software packages they prefer. Users do not need to learn different user inter- faces, because data can be taken in their own, familiar applications. The service can be implemented, for example, based on an existing export/import interface of a GIS software package. Users do not need to pay attention to connect to service computers as their ap- plications are taking care of the communication with the service system.

DATA CONTENT

REPRE- SENTATION

TRANSPORT

EDI Based Geographic Information Service

data description

Description message SFS 5751

Structured data representation JHS 112

Geographic data representation JHS 117

syntax rules EDIFACT ISO 9735

data order

Query message JHS 113

Order message JHS 114

Query by position JHS 118

application detasets

data content dependent messages (JHS)

Info message JHS 115

Geographic data message JHS 119

character set

8-~ts ISO 8859-1

party identification EDI-identifier SFS 5748

framing

OVTIEDl-frame

data transport service

X.400 X.435 TCP/IP (FTP)

OVT/EDI - X.400 OVT/EDI - FTP OVT/EDI-disc OVT/EDI-mgtape

181

FIGURE 2. The Reference Model of EDI Based Information Service. The General EDI Model is Divided into Three Separate Layers. International Standards are Applied in the Transportation and the Representation i.e., Encoding. Generic or Content Dependent Message Types are Described in a Standardised way which is the Basis for Ordering and the Whole Service. SFS Refers to a National Standard and JHS to an Administrative Recommendation in Finland.

S T A N D A R D S

The general three-layer EDI model is the basis for the standards of the EDI based information service. The three layer are transportation, representation and data contents. The reference model standard (JHS 11 I/JHS 116) gives the overall structure of standards needed and points at the international standards to be applied.

In transportation it is common to apply a file transfer service like TCP/IP FTP or electronic mail like X.400. Today, in practise, file transport is much quicker and cheaper.

In representation the EDIFACT (ISO 9735) syntax rules are followed and all data is coded with 8-bit characters (ISO 8859-1). EDIFACT is a reasonable choice because it is well established and widely supported. Many EDI software packages supporting EDIFACT can be found on the market.

Data contents is defined by message descriptions. There are two approaches in EDI message design. Either every database has its own content dependent message type or all databases apply a generic message type which is content independent. In Finland, imple- mentations are based on content dependent message types but a draft of a generic message has been developed. The standard concerning the representation of geometric primitives (JHS 117) has been produced in order to harmonise the representation of geographic data supplied by different systems.

In EDI based information service, a key issue is that every message type is described in a standardised way by using the description message (SFS 5751). The descriptions are the basis for electronic ordering and the query message (JHS 113/118) is derived from the description message. Some spatial operators are defined for retrieving geographic data (Figure 2).

182 A. Rainio

data message

FIGURE 3. Implementation of EDI Based Information Service. The EDI Software is Interoperating with Data Communication Service and Database Management Service. The Kernel of the Software is the EDI Translator. The EDI Management System Includes a Database with Customer Information. Every Transaction is Registered for Invoicing Purposes.

IMPLEMENTATION

Geographic data suppliers are responsible for and free to implement the service. Good support and consultancy is important because EDI tools and standards may be found difficult. A service centre is a beneficial approach when implementing and marketing the service. The most important tasks for a service centre are to maintain the geographic data directory system and to harmonise the data definitions. The service centre can help in message design and even make a contract with a data supplier for implementing the whole service. The service centre may cooperate with software houses and have a role of testing new user applications and giving them some certificates.

Implementation of a Server System

In implementing the server system the first task is to design the message type to be used in the service. The message design is often a joint effort of the supplier, users and an EDI consult, and it may even take several months to find a consensus.

Suitable EDI software can support the implementation of the service in a supplier system. An EDI translator converts the records taken out from a database to EDI message format. The actual data access is implemented with a query interpreter which is able to pick out data following the query parameters given in the query message. The EDI management system interoperates with data communication service. When it receives a query message the rights of the sender are checked before a service process will start. In a simple case it takes only a few days to implement the service (Figure 3).

Implementation of an End User Application

An end user application can be an existing piece of software which is tailored or it can be a new one especially designed for EDI based information service. Different kinds of user applications, like an electronic form or a spreadsheet or desk-top map publishing, are possible. An application should be able to send query messages and receive messages containing response data. The EDI software can support the end user application in forming a query message as well as in translating response messages (Figure 4).

EDI Based Geographic Information Service 183

Electronic form Spreadsheet Map interface

mQUery I D a t a o s s a g e rj ~ message

e / Enterprise data 8 @ En 'ronment a

Statistic data Natural resource data

FIGURE 4. End User Applications. User Applications can be Built Quickly with Existing Application Development Tools. Applications Should Make Use of EDI Software and Data Transport Services. In Finland the First Geographic Data Extractor in the Market is Based on Maplnfo. Another Based on ArcView2 is Coming to the Market Soon. Both of them are Able to Retrieve Data from More than Ten Different Databases and Ordering is Supported by the Base Map 1:20,000 of Finland on a CD-Rom.

BUSINESS

The EDI based information service allows full distribution of data maintenance. For the quality reason especially, it is important that data is maintained near its place of birth. So geographic data suppliers are, in principle, independent to implement the service. The data suppliers are responsible not only for the data maintenance but also for data security and privacy. In EDI based information service the suppliers have full control on data and they can supervise and monitor the usage of data. If the data is not public the permissions on data access are given by the supplier.

Service Centre

Therefore, a critical mass is needed before the service will be successful and the investment will be profitable. Being aware of costs and in order to be customer oriented, data suppliers should cooperate and establish a service center, not only for technical reasons but for also sharing the marketing costs and efforts.

In the geographic information business a service centre needs three types of agreement with three types of parties: customers, suppliers and other service centres. A customer should get access to as many geographic databases as possible with a single agreement and an invoice should contain the usage of all external information services. A service centre is a reseller of geographic data. A data supplier should make an agreement with the service centre through which the supplier would get in touch with all customers of all the other data suppliers. In practice, several service centres may exist at the national and the

184 A. Rainio

international level. They should agree how they resell their services to customers of each others. In Finland the Geographic Information Centre is starting a service centre activity.

Prices and Payments The EDI based information service is a new approach to the geographic information

business. Traditionally, negotiations and manual operating is needed when a customer buys a file on a disk or on a tape in a format which should be applicable for his/her system. However, it is possible to receive only the requested amount of data without any manual operations. Data is a response to a query and, therefore, the value of that special piece of data is much higher than the value of data in general. A customer needs to buy only those pieces of data which he/she really needs and has not any accessory costs of updates. If the unit price is the same data in EDI based information service can be much cheaper to a customer than in traditional delivery system.

It is obvious that in the beginning end users have to pay extra in order to be able to use EDI based information service directly from their applications, but soon this capability will become an asset in competition and a normal qualification of a GIS package. A service centre will probably collect an annual customer payment and charge data suppliers a commission for the resold data.

CONCLUSION

The EDI based geographic information service is a way to develop the geographic infor- mation business. It is a result of cooperation and interwork of organisations who are willing to ensure that their databases are useful in a society. The data network is removing barriers between systems and locations. The national geographic information infrastructure is born in Finland (Rainio and Ahonen, 1994).

REFERENCES

Rainio, A. & Ahonen, E (1994). EDI and Joint Use of Geographic Information, 17th Urban Data Management Symposium/Workshop proceedings, Espoo.