More than road maps

Standards are key for bigger geographic information systems

RFP Checklist: Geographic information systems

When developing a geographic information system, standards are the biggest concern. Because GIS technology is expanding to encompass a wider variety of data sets, the solution must integrate all the information that the customer plans to use. Here's what to ask for in a standards-compliant GIS:

» Does it use an OpenGIS-compliant data store? Many database vendors and open-source database projects support OpenGIS-compliant spatial data and varying levels of geospatial query functionality. Being able to connect to a database platform for which there are already licenses can cut costs and aid integration with other applications.

» Does it support GML? The OpenGIS Geography Markup Language, a key part of the Federal Geographic Data Committee's framework for the National Spatial Data Infrastructure, simplifies the exchange of shared information sets and the building of Web-based geospatial applications.

» Can it import schemas through Unified Modeling Language? The Federal Geographic Data Committee's seven framework themes are constructed in Unified Modeling Language, so support is needed to bring in UML schemas.

» Does it have Spatial Data Transfer Standard support through Part 7 of the standard? The standard is critical for moving data from one GIS to another or to import data from computer-aided design and drafting systems, raster images and geographic-point data from surveys and other high-precision geodetic data.

» Does it comply with the Cadastral Data Content Standard? The Cadastral Data Content Standard allows integration of public land records with GIS data. It standardizes data and objects, including survey measurements, general property descriptions, and boundary and corner data for land parcels. This applies to any GIS covering geography in the United States and its territories.

» Does the GIS incorporate methods based on the National Standard for Spatial Data Accuracy? For data such as digital ortho-imagery (straight-down, two-dimensional aerial or satellite imagery) and elevation data to integrate with the National Spatial Data Infrastructure, it needs to comply with the National Standard for Spatial Data Accuracy. Ask about pass-fail criteria for GIS products based on acceptable levels of accuracy in each application.

When it comes to government operations, nothing grabs citizens' attention like geographic information systems. The powerful combination of maps, imagery and geographically linked data has become key to handling everything from the most mundane of tasks, such as tracking weather, crops and drought, to the urgent needs of first responders and intelligence workers monitoring homeland security threats.

The definition of GIS has expanded far beyond matching maps to data points. Increasingly, agencies are combining map information with other, real-time information and enterprise data to create new location services and applications.

The need to push timely, accurate information to people in the field is driving a new generation of GIS-enabled devices and intricate, Web-based collaboration tools that incorporate geospatial data.

Building or incorporating GIS applications into an agency's IT infrastructure, however, requires a working knowledge of the emerging standards that let data be shared with another group's systems and a user's own applications.

The Google effect

The world of GIS and geospatial intelligence applications, programs that relate location data to maps or satellite imagery, has never been more accessible to government agencies thanks, in part, to commercial applications such as Google Earth.

Available as a free download or in professional and enterprise editions, Google Earth combines various location information into an orthogonal (straight-down, two-dimensional) view or a three-dimensional view.

Although Google Earth isn't GIS, it and its sibling, Google Maps, are quickly becoming a standard for location-based Web applications. In August, the National Geospatial-Intelligence Agency recognized Google for its contribution to relief efforts during Hurricane Katrina and its aftermath. Many private and public agencies, including the Federal Emergency Management Agency, used the company's imaging and mapping technologies to track the storm, monitor relief operations and dispatch aid.

Another use of geospatial data is emerging on mobile phones in Japan: point-and-click geographic search tools based on a compass and a Global Positioning System integral to the phone. The technology, developed by GeoVector Corp. of San Francisco, is available on commercial handsets from Sony Ericsson, and uses a mix of terrestrial radio signals and GPS to fix a user's location within 30 feet, even among tall buildings where satellite signals might be blocked.

"The broad stroke of GeoVector is connecting people with the world around them," said Peter Ellenby, director of new media at GeoVector. "It could be extremely helpful for many types of homeland security applications."

Because the technology runs on readily available devices, Ellenby said, government agencies could distribute handsets to first responders and offer the application over a private cellular network. By pointing a handset at a building, or even a manhole cover, first responders could access information about the item and its surroundings.

Standards needed

Such applications require up-to-date, if not real-time, data. Most GIS data could hardly be called timely; mobile users usually got it from a CD-ROM. But like most enterprise applications, GIS has become more time-sensitive.

With new systems that support a wide range of clients, standards for geospatial data have become more critical. Although standards can get systems half way there, emerging commercial and open-source standards for geospatial applications are at their limits.

"The typical market was power GIS users doing things on a desktop," said John Steffenson, manager of the federal market team for ESRI Inc., which develops the ArcGIS platform of geospatial software. "But like a lot of applications, GIS has moved from being on a few desktops toward being an enterprise application. And not just enterprise as in a single organization, but now with the Federal Enterprise Architecture and the Geospatial Line of Business, it's across the entire federal landscape, which is daunting, to say the least."

Geospatial Line-of-Business efforts and National Spatial Data Infrastructure (NSDI) development aim to simplify geospatial data-sharing and reducing duplication of effort.
"The Geospatial Line of Business is changing the landscape, but how fast and how successful those changes will be remains to be seen," Steffenson said. "There are some early indicators that it's working."

Examples of early successes Steffenson cited are Geospatial One-Stop (www.geoda, the Interior Department's portal for local, state and federal geographic data, and the Bureau of Land Management's National Integrated Land System (
nils). Last fall, the Health Resources and Services Administration won an award from Washington Technology sister publication Government Computer News for its Geospatial Data Warehouse, which puts health information on a map and makes it available to others, such as the Environmental Protection Agency.

The road traveled before

The drive for standardization isn't new. The Office of Management and Budget's Circular A-16, issued in 1990 and revised in 2002, requires all agencies to comply with NSDI standards as specified by the Federal Geographic Data Committee, which the Office of Management and Budget formed when it first promulgated the circular.

To increase interoperability of data from different GIS applications, the committee has proposed a set of standards, collectively called the Framework Data Content Standard.

Seven NSDI framework themes are being developed as part of the standard. They describe how to store and share data on digital ortho-imagery (aerial and satellite imagery captured from directly above an area), land ownership data, geodetic control and elevation data, hydrographic and transportation data, and governmental unit boundaries.

The Framework Data Content Standard relies on the Object Management Group's Unified Modeling Language to define GIS schemas, or definitions of how to put geographic data into Extensible Markup Language, and the Open Geospatial Consortium's Geography Markup Language, which is part of the consortium's OpenGIS standards. The Unified Modeling Language models and Geography Markup Language files for each theme are downloadable from the Federal Geographic Data Committee's Web site.

The committee also mandates some naming conventions and other standards for government GIS work. The first is the American National Standards Institute's Spatial Data Transfer Standard, which provides a format for archiving geospatial data and moving it among different GIS platforms. After 12 years of development and testing, the U.S. Geological Survey in 1992 published the standard, which it continues to maintain. The standard became part of the Federal Information Processing Standards two years later and was approved as an ANSI standard in 1998.

But that standard is designed primarily for pushing large data sets between GIS systems, not for use by distributed applications. Because such data includes all of the raster (bit-mapped) graphics of maps and other presentation data in full resolution, publishing it across a WAN requires a lot of bandwidth. Because GIS data sets are so large, agencies often must divide the data into pieces for transmission.

ESRI, Oracle Corp. and other vendors of geospatial applications generally have embraced OpenGIS standards. However, with mobile and Web-based GIS applications on the rise, and with Google and others offering geospatial applications, vendors are moving to support the Keyhole Markup Language, the metadata format that Google Earth uses.

Keyhole Markup Language is based on ? but doesn't directly support the import of schemas built into ? Geography Markup Language. While the geography language is designed to describe content and relies on other technologies to render that information as graphics or text (including HTML and the Vector Markup Language), Keyhole Markup Language is designed for creating "place marks," map overlays marked with places that users define, for the Google Earth application.

Geography Markup Language can be used for a GeoWeb application, one that presents geospatial data through a Web client, but the main advantage of Keyhole Markup Language is that it can leverage Google's geographic search platform.

Fortunately, the GIS platforms most prominent in the government (ESRI's ArcGIS, Intergraph Inc.'s GeoMedia and AutoDesk Inc.'s Map2D and Map3D) can export Keyhole Markup Language files, which means that agencies need not decide between the two markup languages.

That flexibility is critical as GIS applications move toward the Web. It's important for agencies to embrace standards at the core of the NSDI, but they need to watch emerging commercial specifications such as the Keyhole Markup Language.

S. Michael Gallagher is a technology writer in Baltimore.

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