Sharing Spatial Data Across Borders

October 17, 2006 By: Sam Bacharach, Douglas Nebert

When two countries share a border, they have many reasons to share geospatial information about the border region. More often than not, data collected along one side of the border for purposes such as urban planning, transportation planning, natural resource and environmental management, business geographics, and infrastructure management can be useful to people engaged in similar activities across the border. It is also the case — on both sides of the border — that data collected for use in one domain of activity have value in other domains.

It’s easy to understand how some of the data developed for civil and commercial uses (like those described above) could be useful in border security planning and monitoring. However, it is harder to predict which data will be useful in managing a specific border security incident until the incident unfolds.

Both predictable and unpredictable data sharing requirements call for cross-border data coordination and systems compatibility planning. But, as geospatial data veterans know, such coordination and planning is difficult enough without having to deal with cross-border jurisdictional issues. Fortunately, recent advances in the world of geoprocessing standards have made things much easier.

On the Same Standards Track

Traditional sharing of bulk data files by means of bulk transfers and bulk conversion to a usable format – a time-consuming process -- is less critical once “services” that provide ready-to-use data become available. Bulk transfer is not going away any time soon, but the fluid nature of many incidents is better served by near real-time data provision via Web services. Web services provide the flexibility needed to stay current, and bulk transfer and data conversion, when needed, accommodate systems that the Web cannot support. Fortunately, the U.S. and Canadian governments have been implementing the ability to do both using the same standards. Government agencies in both countries have been moving in the direction of geospatial data sharing through systems that interoperate by means of conformance to common interface and encoding standards. Agencies from both countries have participated in International Organization for Standardization (ISO) technical committees and in the Open Geospatial Consortium, Inc. (OGC) to help develop international standards that meet their nations’ needs. Now that some of these standards are implemented in products and deployed on a large scale in both countries, cross-border interoperability is increasingly a reality. Both the United States and Canada are moving toward broader adoption of Web service-based delivery of government geospatial information.

GeoConnections is the government-sponsored program that deploys the Canadian Geospatial Data Infrastructure (CGDI). The CGDI is a “national initiative to provide Canadians with a spatial information infrastructure over the Internet.” GeoConnections is administered by Natural Resources Canada, which identifies and endorses standards to which applications and services must conform in order to comply the CGDI, which is based on Web services. Conformance is very important to ensure that CGDI components are interoperable, no matter which government or private sector entities develop and maintain them. GeoConnections’ Discovery Portal is the clearinghouse/discovery mechanism for discovery of geospatial information holdings in Canada. Other Canadian government data portals such as ResEau (water resources and environment) use the same standards infrastructure as the Discovery Portal.

The GeoConnections program adopts international or national standards, partly so that the CGDI can be interoperable with other infrastructures around the world. Thus, services or applications that conform to CGDI-endorsed specifications are very likely able to operate or interface with other components outside of the CGDI. (Standards, of course, confer other benefits, such as increased competition among vendors and greater flexibility in choosing and integrating products.)

In the United States, the Federal Geographic Data Committee (FGDC) oversees the development and maintenance of the U.S. National Spatial Data Infrastructure (NSDI). The FGDC has membership from 17 federal agencies and collaborates with state and local government entities and professional organizations in defining common coordination, policy, and standards guidance for the national geospatial community. The Secretariat of the FGDC is hosted by the U.S. Geological Survey (USGS) within its National Geospatial Programs Office (NGPO). This office also administers The National Map, which provides integrated electronic base maps, and the Geospatial One-Stop (GOS) Portal, also known as “geodata.gov,” which supports information discovery and access.

The geodata.gov portal provides Web access to geospatial resources including data and services. It provides access to a catalog of geospatial information containing thousands of metadata records (information about the data) and links to downloadable datasets. Metadata may also include links to Web services that implement the OpenGIS Web Map Service (WMS), Web Coverage Service (WCS), and Web Feature Service (WFS) implementation specifications. These services can be loaded in a viewer window with maps from any other server, or, in the case of WFS, may be directly accessed or downloaded as data by the user. The metadata records are generally served through catalogs by government agencies (local, tribal, state, and federal), individuals, and companies. These are accessed by the portal, where they are harvested and indexed to accelerate search. The automated harvesting and indexing of data in the distributed catalogs is enabled by the fact that the catalogs all implement the OpenGIS Catalogue Service Implementation Specification.

Ultimately, GOS will be functionally identical to the CGDI and accessible through the same clients and browser-based applications, as shown in Figure 1.

Figure 1: U.S. and Canadian portals are based on essentially the same open Web-based architecture. Courtesy of “NSDI Clearinghouse and Geospatial One-Stop Portal” presentation by Michelle Anthony and Doug Nebert of the FGDC Secretariat, April 2006.

Currently, FGDC is collaborating with the European INSPIRE initiative and with Canada’s GeoConnections on common problems and in support of the Global Earth Observation System of Systems (GEOSS). The model is one of a “Global Spatial Data Infrastructure” based on multiple interoperating service registries like those shown in Figure 2 below.

Figure 2: “GeoNetwork Portals” shown in the figure are based on a non-proprietary, standardized and decentralized “GeoNetwork opensource” spatial information management environment, designed to enable access to georeferenced databases, cartographic products, and related metadata from a variety of sources. Courtesy of “NSDI Clearinghouse and Geospatial One-Stop Portal” presentation by Michelle Anthony and Doug Nebert of the FGDC Secretariat, April 2006.

Cross-Border Infrastructure Protection Initiative

The city of Windsor in Canada and the city of Detroit in the United States worked with county, state, provincial, and national agencies, as well as companies and local universities, in the OGC’s first “Critical Infrastructure Protection Initiative,” CIPI-1, which concluded in March 2003. The pilot project demonstrated how new standards available at that time could enable real-time, cross-jurisdictional data sharing (see Figure 3).

The fictional scenario in CIPI-1 involved a chlorine spill near the Ambassador Bridge border crossing. Having configured their systems with interfaces that implement OGC standards, officials from the various agencies easily established a geographic picture for the area at risk; notified the media and emergency response teams, built up situational awareness and developed time-series visualizations, assessed risks, and planned an evacuation.

Figure 3: CIPI-1 Open architecture concept serves cross-border cooperation during emergencies.

When all agencies at all levels use the same open architecture, any agency’s geospatial resources can be made available to all other agencies at a moment’s notice through Web services, without the need for system-to-system integration or batch file transfers. The necessary ISO and OGC Web Services standards are available now. The deployed Canadian national program is based on these standards, and the U.S. program is well on its way to becoming a Web services-based system that uses the same open standards that the Canadian program uses.

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