When X doesn't mark the spot

With more agencies building geographic information systems, standards are key to making them work right

Geographic Information Systems

Much of what you need to consider when shopping for a geographic information system has to do with standards. Because GIS technology is expanding to encompass a wider variety of data sets, make sure the solution you look at can integrate all the information you plan to use. Here's what to ask for in a standards-compliant GIS:

  • Does it use an OpenGIS-compliant data store? With many database vendors and open-source database projects supporting OpenGIS-compliant spatial data'and varying levels of geospatial query functionality'being able to connect to a database platform you already have licenses for can cut costs and aid integration with other applications.

  • Does it support GML? The OpenGIS Geographic Markup Language is a key part of the Federal Geographic Data Committee's framework for the National Spatial Data Infrastructure and makes it easier to pass shared information sets back and forth and to build Web-based geospatial applications.

  • Can it import schemas through UML? The FGDC's seven framework themes are constructed in Unified Modeling Language, so you'll need support for bringing in schemas from UML.

  • Does it have Spatial Data Transfer Standard support through Part 7 of the standard? STDS is critical for being able to move data from one GIS to another, or to pull in 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 CDCS allows integration of public land records with GIS data. CDCS 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 to enforce data accuracy based on the National Standard for Spatial Data Accuracy? In order for data such as digital orthoimagery (straight-down aerial or satellite imagery) and elevation data to play well within the NSDI, it needs to comply with NSSDA. Ask about 'pass-fail' criteria for GIS products based on acceptable levels of accuracy in each application.

  • If the system is to be used to track utility systems and other infrastructure, does it comply with the Utility Content Data Standard?

  • Does the system provide a way to display GIS data through Web-based programs and mobile clients?

When it comes to government operations, perhaps nothing gets citizens' attention like geographic information systems. The powerful combination of maps, imagery and geographically linked data has become key to everything from workaday tasks such as weather, crop and drought tracking, to the urgent needs of first responders and intelligence workers monitoring threats to homeland security. And that's just the beginning.

The definition of GIS has expanded far beyond matching maps to data points.

Increasingly, agencies are combining map information with real-time information and enterprise data to create new, location-based services and applications. Plus, 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 into your agency's IT infrastructure, however, requires a working knowledge of the emerging standards that will allow you to share data with another group's systems and your own applications.

The Google effect

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

Google Earth, available as a free download or in professional and enterprise editions, combines location-based information of all sorts into an orthogonal (straight-down) view or a 3D-perspective view.

Although Google Earth itself isn't a traditional GIS, it's quickly becoming a standard for location-based Web applications, along with its sibling, Google Maps.
Organizations are using the technology to handle everything from tracking taxicabs to plotting crime trends. [For more on Google 'mash-ups' that incorporate geospatial data, see our story on composite applications at GCN.com, GCN.com/663.]

In August, the National Geospatial Intelligence Agency recognized Google for its contribution to relief efforts during Hurricane Katrina. 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 application 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 within 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. 'But you could think of many government applications. 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 provide the application over a private cellular network riding on existing infrastructure. By pointing a handset at a building or even a manhole cover, first responders could access information about the item of interest and its surroundings.

The need for standards

Applications like these are the future of GIS. But in the past, GIS data could hardly be considered timely'mobile users typically got it from a CD-ROM. Today GIS, like nearly all enterprise applications, has become more distributed and time-sensitive.

So, as new systems come out that support a wide range of clients, standards for geospatial data are more critical. Although existing standards can get systems part of the way there, emerging commercial and open-source standards for geospatial applications are at their limits.

'The traditional 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.'

The efforts around the Geospatial LOB and development of a National Spatial Data Infrastructure are aimed at simplifying the sharing of geospatial and reducing the duplication of effort.

'The Geospatial Line of Business is changing the landscape, but how fast and how successful those changes are going to be remains to be seen,' Steffenson said. 'We're early into that, but there are some early indicators that it's working.'
Steffenson points to Geospatial One-Stop (www.geodata.gov), the Interior Department's portal for local, state and federal geographic data, and the Bureau of Land Management's National Integrated Land System (www.blm.gov/nils) as examples of early successes. Last fall, the Health Resources and Services Administration was recognized with a GCN Award for its Geospatial Data Warehouse, which puts health information on a map and makes it available to other groups such as the Environmental Protection Agency [see GCN.com/664].

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

In an effort to make exchange of data between GIS systems more effective, FGDC has proposed a core set of standards, collectively called the Framework Data Content Standard.

Seven NSDI framework themes are being developed as part of the standard, describing how to store and share data on digital orthoimagery (aerial and satellite imagery taken 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 for the definition of GIS schemas and the Open Geospatial Consortium's Geographic Markup Language, which is part of the latter's OpenGIS standards. The UML models and GML files for each of the seven framework themes are downloadable from FGDC's Web site [GCN.com/665].

In addition, FGDC mandates a number of 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 both archiving geospatial data and moving it among different GIS platforms. After 12 years of development and testing, the standard was published in 1992 (and is still maintained) by the United States Geological Survey, SDTS was made part of the Federal Information Processing Standards two years later and approved as an ANSI standard in 1998.

But SDTS is designed primarily for pushing large data sets between GIS systems'not for distributed applications. The bandwidth required to publish SDTS data across a WAN can be daunting, because SDTS includes all of the raster graphics of maps and other presentation data in full resolution. Because GIS data sets are so large, agencies often have to break their information up into multiple pieces so they can be transmitted at all.

A new wrinkle for products

ESRI, Oracle Corp. and other vendors of geospatial applications (see chart) have generally embraced OpenGIS standards. However, with mobile and Web-based GIS applications on the increase, and with Google and others offering geospatial-based applications, vendors are also moving to support the Keyhole Markup Language, the metadata format used by Google Earth.

KML is based on GML, but it doesn't directly support the import of schemas built in GML. While GML is designed to describe geographic content and relies on other technologies to render that information as graphics or text (including HTML and the Vector Markup Language), KML is designed specifically for creating 'placemarks' for the Google Earth application.

So while it's possible to use GML as the basis for a so-called GeoWeb application'one that presents geospatial data through a Web client'the main advantage of KML is that it can leverage Google's popular geographic search platform.

Fortunately, the GIS platforms most prominent in the government (ESRI's ArcGIS, Intergraph's GeoMedia and AutoDesk's Map2D and Map3D) can export KML files. Therefore, agencies don't face an either-or decision between GML and KML.

And that flexibility is critical, as GIS applications increasingly move toward the Web. While it's important for agencies to embrace standards at the core of the National Spatial Data Infrastructure, they need to keep an eye on emerging commercial specifications such as KML.

As GIS evolves into an enterprise platform like ERP, agencies will want to deploy geospatial data in whatever form necessary, whether the client is a GPS-capable cell phone or a desktop analysis application.

S. Michael Gallagher is a technology writer based in Baltimore.

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