1 Introduction

Spatial Data Infrastructure (SDI) is generally defined as the collection of technologies, policies and institutional agreements that facilitate the availability of and access to spatial data. The SDI provides a basis for spatial data discovery, evaluation, and usage for users and providers within all levels of government, the commercial sector, the non-profit sector, academia, and by citizens in general (GSDI 2009).

Geospatial data is crucial for a wide variety of government and private sector activities because it helps provide context for analysis, planning and decision support. After being struck by a natural disaster, for example, a region not only needs current and complete data (such as maps of roads, buildings that can serve as shelters, and places to land helicopters) it also needs to update maps and make them available as fast as possible for response and recovery operations. Unfortunately, geospatial data publishing is done by numerous participants whose information systems use various different formats and protocols, and in the past this made it difficult to access, integrate and use the data. Government agencies, communities and research institutions rely on both off-the-shelf and custom-made software products that often do not interoperate seamlessly.

Fortunately, providers of these software products, following the trend in the larger information technology (IT) world, are moving rapidly toward ubiquitous use of internationally accepted open interface and encoding standards that enable interoperability. Interoperability between diverse distributed systems makes possible more options in procurement and more options in SDI policy.

The OGC is a standards development organization (SDO) focused on providing such geospatial interface and encoding standards. This article provides information, about the OGC, exemplar projects, the value of standards and the importance of OGC and standards in Spatial Data Infrastructures. As more offices in government and businesses in the private sector begin producing and hosting data and as the open standards-based Web becomes the dominant delivery mechanism, Spatial Data Infrastructures (SDIs) become increasingly valuable to governments, citizens and commercial enterprises at all levels.

Figura 1

2 The Open Geospatial Consortium

2.1 OGC Overview

The Open Geospatial Consortium (OGC) is a nonprofit, international, voluntary consensus standards organization, founded in 1994. The OGC leads the development of standards for geographic content and services, sensor webs, and location services. The OGC’s mission is to help realize the full societal, economic and scientific benefits of integrating electronic location resources into commercial and institutional processes worldwide. The OGC manages a process in which developers and users of spatial data products and services collaborate to develop and promote international standards for geospatial interoperability. In October 2011 the OGC membership consists of more than 435 geospatial technology software vendors, systems integrators, government agencies and universities.

The primary product of the OGC is “standards”. An OGC standard is a document that details the engineering aspects and rules for implementing an interface or encoding that solves a specific geospatial interoperability problem. In a formal consensus process, the contents of standards documents are defined, discussed, tested, and approved by the members. The standards are designed to support interoperable solutions that “geo-enable” the Web, wireless and location-based services, and mainstream IT. They empower technology developers to make complex spatial information and services accessible and useful to all kinds of applications. As of October 2011, more than 40 standards have been published by OGC.

The OGC is not the only SDO. Other SDOs specialize in domains other than geospatial technology. The OGC collaborates with them, reusing their technology and helping address their requirements for location. These SDOs include such organizations as the International Organization for Standardization (ISO) Technical Committee 211, the Organization for the Advancement of Structured Information Standards (OASIS), the Internet Engineering Task Force (IETF) GeoPriv Working Group, National Emergency Number Association Next Generation 911 (NENA), the Open Mobile Alliance (OMA) and the World Wide Web Consortium (W3C).

The OGC also has partnerships with other organizations, such as the Global Spatial Data Infrastructure (GSDI) Association, whose members have an interest in sharing geospatial resources.

2.2. OGC Reference Model

The OGC Reference Model (ORM) describes the OGC Standards Baseline and explains relationships between OGC standards and standards from other SDOs (Percivall, Reed et al. 2008). The OGC Standards Baseline consists of the approved OGC Abstract and Implementation Standards. These include interface, encoding, profile, application schema, and best practice standards.

When developing a standard it is important to avoid dependencies on technologies that could become obsolete in the near future. For this reason, the OGC membership usually begins by developing reference architectures that provide abstract elements of a domain independent of the technologies, protocols and products that are used to implement domain solutions (OASIS Committee Specification 2011). The OGC makes use of the ISO Reference Model for Open Distributed Processing (RM-ODP) (ISO/IEC1998) which provides a useful guide for technology neutral development. The RM-ODP recommends careful documentation of requirements from several view points, such as:

2.3 OGC standards

OGC Web Service standards follow the definition of a Web service originally proposed by IBM, Motorola and others (Vasudevan 2001).

A service is a set of interfaces with a particular functionality provided by an entity (ISO 2005). An interface is a named set of operations that characterize the behavior of an entity (ISO 2005). An operation is a specification of a transformation or query that a service may be called to execute (ISO 2005). An encondig, usually what the service returns, is data converted into code, such as XML (ISO 2011).

When OGC standards are implemented in products or on line services by two different software engineers working independently, the resulting components plug and play, that is, they work together without further debugging.

The SDI Cookbook (GSDI 2009) summarizes the OGC service framework, and categorizes the services by purpose or functionality. It distinguishes the following main types of component services:

A few of the most widely implemented OGC standards are described below:

As of October 2011 there are 35 adopted OGC standards. They enable geospatial interoperability in areas such as:

Briefly stated, OGC standards are making geospatial information an integral part of the world’s information infrastructure. If there were no organization like the OGC working toward this goal, the inherent complexity of geospatial information and geoprocessing would perpetuate the reality of geospatial information being locked up in expensive proprietary systems.

3 Exemplar Projects

Geospatial “communities of interest”, whether the communities span small geographic areas or the whole Earth, benefit in many ways from adopting OGC standards because these standards make it much easier to share geospatial data and processing resources. That is, they make it easier to publish, discover, assess, access and combine geospatial data and geoprocessing resources available from multiplesources in multiple locations. Two examples are showcased in this section: the Geology Community and the GEOSS (Global Earth Observation System of Systems) community, an international team developing a global architecture to share Earth Observation (EO) data.

3.1 The Geology Community’s One Geology

The international geology community has come together in a global project (One Geology) that successfully produced the first online digital geological map of the world. As of October 2011, 117 countries are participating.

One Geology is underpinned by GeoSciML, WMS and WFS. GeoSciML is an encoding standard developed by the Interoperability Working Group of the International Union of Geological Sciences (IUGS) Commission for the Management and Application of Geoscience Information. GeoSciML is a GML application schema. Implementations of the OGC WMS standard provide access to the geological maps and access to the geological data that is returned in GeoSciML.

Figure 2 depicts the participants in a GeoSciML Testbed. Each participant stores their data in their own database, using their own schema, data model and semantics. They agree to use WMS and WFS interfaces and GeoSciML as the encoding standards to allow GML clients to access and integrate the data seamlessly.

Figura 2

3.2 GEOSS Architecture Implementation Pilot

GEOSS (Global Earth Observation System of Systems) is a program of the Group on Earth Observations (GEO), a partnership of 124 governments and international organizations. The ongoing GEOSS Architecture Implementation Pilot (AIP) (Group on Earth Observations 2010), led by the OGC, leads the incorporation into GEOSS of contributed components consistent with the GEOSS Architecture using a GEO Web Portal and a Clearinghouse search facility. The GEO Web Portal and Clearinghouse provide access to services through GEOSS “Interoperability Arrangements” in support of the nine GEOSS Societal Benefit Areas shown in Figure 3 below.

Figura 3

Interpoerability Arrangements consist of policy agreements and online data and processing resources that have been set up based on shared, open standards. These arrangements enable continuous monitoring of the Earth and access to a vast shared set of information resources. Results of the AIP will be transitioned to GEO Task AR-07-01 (Persistent Operations) and the GEOSS Common Infrastructure.

Many science problems are multidisciplinary, use a variety of sensors and require community agreements on standards, such as those provided by GEOSS. For example, ocean scientists need to fuse stored and real-time data from in situ and satelliteborne sensors and traditional digital maps to create useful information. Such information contributes to enhanced policy decisions in areas such as marine ecosystem research, surge flood warning, and climate monitoring. The cost-efectiveness of data collection and software development is multiplied many times when many researchers have a standards framework that enables them to easily share sensors, sensor observations and processing resources. Data collection can be planned cooperatively, reducing redundant collection efforts and improving the return on funding agencies’ investments. Sensor accuracy can be cross-checked more easily. Catalogued data and metadata, in agreed encodings and formats and available on line, enable faster and more accurate data fusion. Web services for data reduction or analysis can be used by multiple organizations, and computational models can be chained with less effort and better quality assurance.

4 Value of Using Standards

OGC members including business, government and academic organizations join the OGC for business reasons. Typically, government executives, research managers, senior sales and marketing profesionals or department heads make the decision to join the OGC and participate in OGC activities. Why? They see in the OGC unique opportunities for learning about the state of the art with regard to interoperability, standards, and applications that implement OGC standards. They also see value in collaborating with their peers in exchanging knowledge across communities of practice. They understand that using standards saves time, money, energy, and sometimes, lives. In addition, government and business leaders understand that influencing and using standards contributes to national economic health.

The OGC Business Value Committee (BVC) engages senior managers and sales and marketing professionals from the OGC membership in activities to identify, organize and promote the business value of OGC standards. The Business Value Committee email list is open to both members and nonmembers.

Organizational needs and agendas drive progress toward interoperability and technology convergence. Different communities of interest have different but overlapping needs and agendas, and often these communities must share information. The OGC consensus process provides members numerous opportunities to express interoperability requirements and work together to shape the OGC standards to meet those requirements. Members take advantage of both the standards and the partnership opportunities to “connect the dots” between different information systems and application domains. The key value of technical interoperability is that it facilitates organizational cooperation and effectiveness. Implementing OGC standards facilitates data sharing, while participating in OGC activies facilitates multi-community and cross-domain cooperation.

Much of the OGC standards work begins in OGC Interoperability Program (IP) test beds, pilot projects and interoperability experiments. In these rapid prototyping activities, each sponsor’s investment is leveraged by the investment of other sponsors as well as in-kind participation by other OGC members, thereby reducing each sponsor’s share of the initiative´s cost and increasing the return on each sponsor´s investment. The ratio of contributions by one sponsor of OGC initiatives to contributions by other organizations is typically between 1:1 and 1:4.

Besides the levarage of cost-sharing, there is the further leverage that results from more soponsors attracting more technology provider participants. Technology providers contribute significant resources to develop, test, and demonstrate the ability of emerging or existing OGC standards to address sponsors’ interoperability requirements. When there are more sponsors and more technology “threads” involved in an OGC interoperability initiative, there is more incentive for technology providers to get involved.

For sponsors, a key attraction of the Interoperability Program is the increased ability to integrate systems and protect technology investments at a cost that is much lower than the cost of one-off integration projects that use custom interfaces and encodings. These savings come first to sponsors and later to non-member stakeholders around the world.

OGC membership offers an excellent way for governments to work with industry and academia to stimulate economic activity. Open interfaces and encodings generated from OGC initiatives often spark new business successes, which aggregate into regional and national competitive advantage. New and more affordable products and services bring commerce, profit, employment and increased innovation. European public and private sector organizations, for example, have played key roles in the OGC, and European membership now exceeds North American membership. In Europe, there has been remarkable innovation in areas such as urban 3D models, sensor webs and Internet security involving online spatial resources. The OGC Open GeoSMS Standard introduced into the OGC by an organization in Chinese Taipei is resulting in significant business activity there and elsewhere. Small businesses and business units in larger companies employ many people in business activities resulting from such innovation.

Business activity like this delivers the value of open standards to governments working to build SDIs. The OGC’s work in sensor webs, geospatial rights management, service chaining, geosemantics, data quality and other areas helps companies provide value and helps governments provide better services at lower cost. Cost savings through increased interoperability and broad implementation of OGC standards in products lead to wider general use of GIS and other spatial tecnologies. This increases the base of users for Spatial Data Infrastructure, and these users are using the infrastructure to do things that have economic and societal value.

5 Spatial Data Infrastructures and the value of standards

OGC standards as well as complementary ISO standards have become part of SDI “best practices” around the world. Standards lower costs and decrease the time required for systems integration. With wide use of standards-based Web services, “loose coupling” between systems becomes possible. That is, developers of such systems don’t need to know details about other systems that their systems might interoperate with. They only need to know that they have correctly implemented certain standards and that other systems are available that have also correctly implemented the standards.

5.1 Countries and regions using OGC standards in SDIs

5.2 SDIs for local and subnational governments

Many local and state or provincial government agencies and offices worldwide face similar challenges involving planning and providing services for growing populations in an era of serious financial constraints and shortages of resources such as water and fuel. At the same time, many regions are beginning to experience weather – related difficulties that seem likely to worsen as climates change.

All such organizations would like to maximize the value they receive from their investments in geospatial information and related technology. The OGC GovFuture membership program helps decision-makers in local and subnational governments understand open standards and use them to best advantage.

Vendors’ implementations of the OGC’s technical interoperability standards make it technically easy to integrate simple and complex geographic information from almost any source, but technical interoperability alone is not the whole solution. GovFuture provides a forum for knowledge transfer leading to “organizational interoperability. “Gov Future helps local and sub-national governments:

Explaining the value of standards is important, because developing an SDI requires cooperation. The whole idea of an SDI is to make it easy for many different entities to share geospatial information, and this requires those entities to share some of the same values. GovFuture membership helps government officials explain the business value of SDIs to foster support and implementation. The central message is that SDIs support government activities in everything from disaster and risk management to emergency response and municipal operations. Geospatial information has different values, however, for citizens, consumers, businesses, and different government offices and agencies, and thus SDI “marketing” requires some skill. SDIs depend on interoperability, so the “call to action” is “deploy products and services that interoperate through open standards”.

6 Conclusions

As the list of national SDIs above indicates, nations are moving rapidly toward ubiquitous use of internationally accepted open standards. To help organizations advance toward their SDI objectives, the OGC provides an evolving forum and growing offering of tools and processes. In addition to the GovFuture program, the OGC helps members form regional forums, such as the France Forum, ILAF (Iberian and Latin-American Forum), India Forum and Korea Forum. The goals and objectives of OGC’s regional organizations differ as necessary to meet the particular needs and circumstances in their regions. But in general they seek to promote OGC membership, coordinate regional participation in the OGC, and promote policies, co-operative business development initiatives and public/ private partnerships that support the use of OGC standards.

The use of OGC standards in Spatial Data Infrastructures is not new. Its value has been proven in many countries worldwide. The OGC is a standards organization, but it is also a hub for transferring knowledge about SDI-related activities. Just as the value of a digital network grows as the number of nodes increases, the value of a knowledge network grows with the number of networked organizations and individuals. Each world region that begins to engage in organized SDI efforts has particular regional circumstances and requirements, but much of what has been learned and developed previously in other places can be reused and shaped to meet regional needs. The exchange of value is reciprocal. Just as OGC members in Europe, Australia and Chinese Taipei have advanced new OGC standards of value to members in all other regions, regions that are currently under-represented in the OGC, such as Latin American, can be expected to make contributions in the future that will have global value.

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