GDT Releases New Versions of Street and Address Data with Verified Positional Accuracy for Areas Across the U.S.

Business/Technology Editors

CES 2002

LAS VEGAS--(BUSINESS WIRE)--Jan. 7, 2002

Consumer Electronics Show

Realignment efforts offer up to 5-meter accuracy for more than 50

percent of the U.S. population

Geographic Data Technology, Inc. (Lebanon, NH), a developer of premier map databases, today announced the release of new versions of its Dynamap(R) family of street and address products with verified positional accuracy for areas representing more than 50 percent of the U.S. population. GDT has realigned 1.27 million miles of roads throughout the United States to an accuracy level of 5 to 12 meters.

GDT's positional enhancement efforts augment the database accuracy to better model real-world conditions while still maintaining detailed and complete street and address attribute information. The January releases of GDT's Dynamap products represent an 83 percent increase in the number of miles of positionally accurate streets and an 11 percent increase in new streets and addresses over the last year. As the industry's most experienced manager and compiler of geographic data, GDT offers customers detailed, enhanced, coast-to-coast coverage of streets and addresses in the U.S. and Canada for location-based applications such as in-car navigation, personal navigation systems, telematics, and web-based mapping.

To verify and test the accuracy of its realignment efforts, GDT uses the National Standard for Spatial Database Accuracy (NSSDA), the standard released by the Federal Geographic Data Committee in 1998 to replace the obsolete National Map Accuracy Standard. The NSSDA sets an independent, measurable standard to compare the accuracy of digital map databases. Following the NSSDA guidelines, GDT uses a series of field-collected, differentially corrected GPS test points to measure against corresponding points in the database to determine the difference between database and real world coordinates. Using this methodology, GDT consistently achieves accuracy levels of less than 12 meters, with most areas achieving accuracy of 5 to 7 meters.

"This method of testing is expensive and time consuming, but it is the only way to truly gauge ground truth positional accuracy of a digital street file," said GDT Founder Don Cooke. "Unlike methods that measure positional accuracy based on deviation from a publicly available file such as TIGER(R), this method shows the accuracy in relation to the real world - which is what most customers who care about positional accuracy need to know. And unlike methods that use the obsolete National Map Accuracy Standard developed for paper maps, this method accurately measures the accuracy of digital maps. While the NSSDA is more demanding than other methods of measuring database accuracy, we think we owe it to customers to deliver data with objectively and reliably verified positional accuracy measures."

The positional enhancement efforts for GDT's data supplement other enhancement efforts in GDT's ongoing data update process. GDT maintains more than 33,000 relationships with geographic resource providers throughout the Western Hemisphere. The majority of those sources represent city, county, state or other local government agencies who are often the first to know of changes and additions to the street networks within their jurisdictions. These resource providers supply GDT with a constant source of updated information on streets and addresses for incorporation into geographic products ranging from routable street and address networks to telecommunications, postal and census geography. GDT uses a combination of aerial imagery, field verification, and rigorous QC processes to test the accuracy and quality of its data creation process.

"At GDT, we recognize that customers evaluate many things when looking at a digital street database," said Mike Gerling, GDT's president and CEO. "Positional accuracy is only one dimension of comparison, and by itself it means very little. After all, it really doesn't matter how accurate your streets are if you can't find the addresses you need. Geocoding performance has very little to do with positional accuracy; it's really a function of whether the streets and addresses are contained within the database. In a variety of tests by customers and independent groups, GDT has consistently produced exceedingly high nationwide street-level address matches. While lots of people claim high geocoding rates because they match to a ZIP Code level, at GDT we zero in on the street rather than the neighborhood so that customers get true geocoding accuracy."

About GDT

Geographic Data Technology, Inc. is the premier developer of map databases that provide the foundation for location-based applications. With more than 20 years experience in data management and compilation, GDT excels at bringing together a myriad of data resources to create spatial products and services that help businesses and consumers manage, understand and analyze geographic relationships. GDT provides cartographic data to major GIS vendors and is the data provider for leading software and web mapping programs. GDT data is used for routing, web mapping, emergency response, site selection, risk analysis, facilities management, and a host of other applications. With a focus on nationwide coverage, GDT offers customers complete, current and comprehensive geographic products for North America, Brazil and Argentina. GDT employs more than 500 people at its Lebanon, NH headquarters. For more information, visit the GDT web site at www.geographic.com.