1.6.1 Framework of Geostandards

From Geostandards

Contents 1 Framework of Geostandards 2 Force Field 3 How does this framework of standards operate? 4 Metadata 5 Information models 6 Services

Framework of Geostandards

The Dutch framework for geostandards can be found at: [1]. The framework is geared mainly to organising the geo-standards for the descriptions of reality in the context within which the geo-objects or the geo-information are used. It is about the information models used to describe reality, about the relevant metadata and about the services required for exchanging and presenting geo-information over the Internet.

Thanks to the integration of geo information with the electronic government (e-government) 1.4.4 Electronic Government) other standards and shared services can be used for example:

• E- access
• E- authentication
• Numbers

The first step in this direction was taken in version 2.0 of the framework of geo-standards. In the next version which will be partly integrated into NORA 3.0, this will be fully implemented. The interconnection of geo-standards and other more general standards goes for the whole geo-domain and also with other domains. First the interoperability within the own domain is dealt with. Next, the interconnection to other domains that need a higher degree of integration is explored. This relates to the chain approach, in which a problem or subject can no longer be dealt with separately.

Force Field

In this illustration it is shown that standards need to take into account the force fields within which they are developed and applied. If the OGC standards are ignored, then the geo-information cannot be exchanged between GIS systems and, if in the basic model of geo information (NEN3610) the Dutch Basic registration of Addresses and Buildings (BAG) is not taken into consideration, this interconnection cannot be guaranteed either. Working with standards is, therefore, mainly directed to converging, harmonising, and integrating all kinds of initiatives and requirements.

How does this framework of standards operate?

The framework lists the geo-standards that are applicable within the geo-domain in the Netherlands, and are linked to other domains. Since the use of these standards is not required by law, it can only be strongly recommended. On the other hand, however, the GI council decided, in June 2006, that all participants to this council (Ministry of the Interior and Kingdom Relations, Ministry of Defence, Ministry of Economic Affairs, Ministry of Finance, Ministry of Agriculture, Nature, and Food Quality, Ministry of Housing, Spatial Planning and the Environment, Ministry of Transport, Public Works and Water Management, the Land Registry Office, Association of Netherlands Municipalities, Association of Provincial Authorities, Association of Water Boards, and TNO-NITG) will consider themselves to be bound to the framework. The geo-standards of the framework will be added to the list of open standards (view [[2]].

The framework, formulated by experts working in the field of standardisation was developed in an open and transparent way and was widely discussed within the larger circle. The framework is maintained by Geonovum. It is fine-tuned continually by the government, trade and industry, and notably by suppliers of geo-ICT. The tuning process enables the framework to be developed even further. To propagate the systematic use of the framework and the standards, and in order to keep discussions alive, Geonovum has launched a website all about the geo-standards: http://www.geonovum.nl/geostandaarden.

The framework is subdivided into metadata, information models and network services. These subdivisions are used in INSPIRE as well.

The same format is used in each chapter and is as follows:

• What are (in this case) metadata?

• How does it operate?

• International/European context

• Model of reference (for standards)

• The standards that are to be used for the Netherlands

• Future developments

Metadata

View module 2 Metadata

Information models

View module: 4 Information Modelling

The following presentation offers insight into the information models:

Presentatie Informatiemodellen

Using an example for the geo-object ‘road’, the process of harmonisation and the use of an information model is explained.

We can define a road by referring to a set of attributes … like its name, its width and its particular identification. One could define these attributes further: the name contains a string, the width is expressed in metres, and the identification requires a unique number. These aspects are part of descriptions of the object ‘road’. However, there is no indication at all as to what is meant by a road. Is the road defined as including a bike path and a pavement? What is meant by the width of the road if it is left unclear what objects are to be counted as part of the object road? We can see that problems such as this belong to the semantics of an information-element: what is the shared understanding of how a road is defined?

In this illustration two organisations have an internal definition for what they mean when they refer to ‘road’. The moment these organisations decide to exchange information about the width of the road, a shared notion is needed of what is meant by width. By way of an example, in the illustration, a model is depicted of the shared interaction domain and its specific information model.

This model contains the shared information that is to be exchanged, and the semantics are added via links. The model specifies that the road consists of a motorway plus a central reservation. Both of these elements have their width specified. A road can also be identified by its identification (Id) and name. The information model to the left contains also an attribute – width - and appears to be defined as the width of the road and the central reservation taken together. The model on the right has more resolution, and contains several parts of a road. If the country on the right is asked to supply the demanded information to the country on the left, this poses no problems, because the width of the road and the central reservation are stored separately. They can be supplied separately or in combination. The organisation on the left can easily interpret the received information by adding the width of both parts of a road and storing that information. A problem for the organisation on the left arises when this party is asked to supply information. Since the organisation on the left does not store the information about the width of each sub-object, it is hard to tell the width of the central reservation from the width of the street.

This example helps to illustrate what the role of an information model is. The thematic working groups of INSPIRE, for example, define such information models for themes from the Appendices I and II.

From this example it is also clear that not all the information can be supplied by both organisations. This can be solved by adapting the internal model of the organisation on the left, or by making arrangements about interpolating information in such a way that the width of the central reservation can be supplied by the party on left after all (for instance by using a fixed measurement for the central reservation).

Services

View module Services

On the one hand, the notion of service has an organisational aspect through which national governments can apply the concept of services-oriented architecture (SOA) in realising their package of services; see, for example, the Dutch Government Reference architecture (NO0052A). On the other hand, this notion has a technical aspect, like the development of INSPIRE, which has a direct and big influence on the Dutch geo- information infrastructure.

The technical approach is chosen when listing geo-standards for geo-services. The INSPIRE and NORA architecture, and the way they combine, is described in 1.7 Architecture.

The specific geo-services are:

• Data services, like WMS, WFS, sensors

• Business services

• Services for process management

• Service registries

The first seven minutes of the film released by the OGC provides a good picture of the geo-services: http://www.opengeospatial.org/pub/www/ows4/index.html.

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