GIS Standards and Interoperability

Standards-based Web services allow content providers to register their data and services so that users can search, locate, and use them.

GIS technology is evolving beyond the traditional GIS community and becoming an integral part of the information infrastructure in many organizations. The unique integration capabilities of a GIS allow disparate data sets to be brought together ("integrated") to create a complete picture of a situation. GIS technology illustrates relationships, connections, and patterns that are not necessarily obvious in any one data set, enabling organizations to make better decisions based on all relevant factors. Organizations are able to share, coordinate, and communicate key concepts among departments within an organization or among separate organizations using GIS as the central spatial data infrastructure. GIS technology is also being used to share crucial information across organizational boundaries via the Internet and with the emergence of Web services.

To fully realize the capability and benefits of geographic information and GIS technology, spatial data needs to be shared and systems need to be interoperable. GIS technology provides the framework for a shared spatial data infrastructure and a distributed architecture. Esri has developed its products based on open standards to ensure a high level of interoperability across platforms, databases, development languages, and applications. Esri is also committed to supporting and actively leading efforts to integrate interoperability and standards in its commercial software products.

The Value of Being Open

An open GIS system allows for the sharing of geographic data, cooperation of different GIS technologies, and integration with other non-GIS applications. It is capable of operating on different platforms and databases and can scale to support a wide range of implementation scenarios from the individual consultant or mobile worker using GIS on a workstation or handheld device to enterprise implementations that support hundreds of users working across multiple regions and departments. An open GIS also exposes objects that allow for the customization and extension of functional capabilities using industry-standard development tools.

A state chief information officer, for example, would expect an enterprise GIS solution to provide a spatial data warehouse supporting shared spatial data and services across multiple agencies such as transportation, environmental protection, natural resources, state police, and information technology (IT). Each agency might also have a local database to update and maintain the framework data for which the agency is responsible and provide an e-government portal for public access. Today's "always on" availability requirements and the growing security considerations also dictate that any GIS solution operates in clustered, high-availability environments and be easily replicated to remote backup server locations.

Esri has a large team of people involved in each of the phases of developing open standards including creating standards, reviewing standards, and integrating standards into our products. Esri also works with a number of standards organizations and directly participates in the creation, review, and introduction of industry standards. Esri's efforts are focused on two major areas:

• GIS data and technology interoperability
• Interoperability of GIS technology with other technologies and systems

GIS Data and Technology Interoperability

Many organizations need a GIS capable of integrating services and data from multiple sources and in different formats. Esri's technology and products support this level of interoperability, and its active role in the development of open standards has helped ensure that Esri data can be easily accessed by other technologies and applications. Esri products support numerous data converters and direct read access of more than 40 formats including Spatial Data Transfer Standard (SDTS), Vector Product Format (VPF), imagery, CAD files, digital line graph (DLG), and TIGER. Of equal importance, Esri systems enable organizations to share GIS services and communicate across different vendor implementations. An open, distributed, and networked GIS architecture provides the framework for sharing data and services.

Interoperability of GIS Technology With Other Technologies and Systems

Esri has also given great attention to the relationship between GIS and the rest of the IT infrastructure. For our users, this means compatibility and interoperability with major enterprise systems such as enterprise resource planning (ERP), customer relationship management (CRM), database management systems (DBMS), work management systems, decision support systems, and others.

GIS software is increasingly used in large multiuser environments in which spatial data is accessed using a variety of platforms and devices from relational database management systems residing on a wide assortment of servers and operating systems. To be open, therefore, a GIS must support platform-independent solutions implemented in heterogeneous environments composed of different server hardware; operating systems; networks; databases; development tools; and desktop, Web, and mobile clients.

Standards Are a Process Resulting in Interoperability

It is important to recognize that standards must support working GIS systems and be practical to implement. They must support users' requirements for interoperability. Esri applies a phased engineering approach to its technical work on standards.

In order to be successful, GIS interoperability is also heavily influenced by, and must fit within, the broader computing industry standards efforts. Technology, such as operating systems, commodity hardware, DBMS, and the Internet, certainly influences interoperability work of the GIS industry. For example, consider the recent development of Web services standards and their potential influence on GIS.

The Web Services Framework

Web services are a new framework of technology and standards for computing. Web services will provide the means to connect a network of distributed computing nodes, which includes a range of devices such as servers, workstations, desktop clients, and lightweight "pervasive" clients (e.g., phones, PDAs), in a loosely coupled fashion. Web services standards are the first attempt at building a foundation through which computers and devices interact to form a greater computing whole, accessed from any other device on the network. It is also important to recognize that Web services are not just for the Internet; they are the next evolution in distributed computing.

A Web services architecture supports the integration of information and functionality maintained in a distributed network via a registry. This architecture is appealing to organizations, such as local governments, that have entities or departments that independently collect and manage spatial data (e.g., roads, pipes, surveys, land records, administrative boundaries). At the same time, many of the functions of a local government require these data sets to be integrated. The use of Web services (a connecting technology) coupled with GIS (an integrating technology) can efficiently support this need. The result is that the various layers of information can be dynamically queried and integrated, while at the same time the custodians of the data can maintain this information in a distributed computing environment.

Looking Forward With Web Services

The GIS community has been pursuing open interoperability for many years, and the solutions to achieving this goal have changed with the development of new technologies. As GIS technology continues to evolve, the question that many organizations are asking today is, "What is the best long-range solution for application/system interoperability?" Esri believes the answer is Web services, an area in which Esri is focusing much of its research and development.

Web services allow GIS users to publish spatial data and functionality to integrate GIS with systems external to the GIS. Web services help avoid many issues and complications that interoperability at the database and application levels can cause. GIS users can manage their data using the best methods and tools of their commercial GIS in whatever database environment they choose, yet publish selected capabilities using an open Web services framework that enables disparate applications to communicate. Web services is a collaborative computing model that enables existing computing nodes and software to work in peer-to-peer relationships. Web services allow server-to-server as well as client-to-server interoperability of data and functionality.

GIS vendors, such as Esri, use relational DBMSs with specific schemas and methods, as well as specialized file formats, to optimize the performance capabilities of their tools. Web services allow each GIS vendor to build and distribute its own GIS products using the best available technology and methods, while at the same time enabling the technology to interoperate with a wide range of external systems, without compromising the design and implementation of the core technology. The result for the GIS user is a distributed GIS computing framework that maximizes performance and functionality internally and interoperability externally.

Web Services and Distributed GIS

This loosely coupled Web services architecture provides a new and promising solution for implementation of complex collaborative applications needed in a distributed GIS. In some ways, the integration of GIS and Web services simply means that GIS can be more extensively implemented, and people will be able to take mapping, data, and geoprocessing services from many servers and integrate them to solve new problems using a common Web service-based environment. Unique to GIS-based Web services is the ability to not only connect and interoperate but also to integrate data using the unique properties that are inherent within GIS itself (i.e., data integration and fusion based on geographic location).

Web services will help to enable many of the shared visions for GIS that have been formulated throughout the last decade to be realized. These include the following:

• The implementation of a spatial data infrastructure (i.e., a distributed network of shared data stores and applications including multiagency and multiorganization participation).
• The fusion of GIS applications (i.e., the ability to bring together multiple GIS applications using geography as the integrated framework). For example, a local government will be able to continuously maintain and update its land records while serving them into other parts of the organization as well as to publish access to external organizations. A utility company could then directly use the basemap of the local government as a replacement for its own basemaps for facility data. A utility company could also serve its facilities data back to the local government for use in permitting and land use planning. This type of interorganizational synergy will dynamically accelerate the use of geographic information everywhere.

Conclusion

Esri has made major investments in the development and implementation of open GIS standards, not only to serve our own customers but also to promote sharing geographic data across all GIS platforms. We believe our continuing investments in Web services will result in the most open and interoperable GIS solution ever deployed. Esri constantly looks to its customers for feedback regarding the value of its initiatives and is especially interested in how our customers are leveraging our investments in interoperability to meet their GIS needs and solve real-world problems.

For further information on standards and to download a white paper on this topic, visit www.esri.com/standards.