NAVTECH Maps from Navigation Technologies (Chicago, Illinois) power nearly every in-vehicle navigation system in North America and a majority of those in Western Europe. The company, a leading provider of digital maps, services customers in the vehicle, Internet/wireless, enterprise/fleet, and government industries. NAVTECH Maps are built by employing a comprehensive development and quality control program, executed by a team of approximately 500 professionals. Quality digital road network maps include more than just the street information. They contain a highly precise representation of the road network geometry; legal driving maneuvers to enable legal and optimal routing; and points of interest such as restaurants, train stations, bus stations, parks, etc. All of this data, covering millions of miles of road network, must be sourced, consolidated, quality checked, maintained, and updated.

Managing these tasks is the responsibility of Navigation Technologies' Digital Mapping Operations (DMO) Division. Since the company's inception in 1985, DMO has been utilizing ArcInfo to build, edit, and test the maps. In more recent years, the company has also used ArcView to analyze data sets. The two primary DMO workforces relying on Esri applications are the digital data engineers and geographers. Navigation Technologies has relied on Esri GIS software because of its functionality; its open platform, making it compatible with many data formats; and its ability to be customized to meet the unique needs of its diverse users.

"Quality is our mandate, which is why we insert quality checks into many phases of our build process," says Navigation Technologies' Greg Edwards, vice president, DMO. "We need to know that the data we license to our customers, in any industry and at any scale, has met all of our quality standards."

Building NAVTECH Maps

The digital map build process begins by collecting and consolidating data from two types of sources: third party data providers and traditional sources such as paper maps and raster imagery. The digital data engineers procure, analyze, and integrate third party data, forming a basemap that will eventually be verified and attributed by a team of field analysts who drive millions of miles of roadway each year. Tasked with ensuring that all third party data meets Navigation Technologies' quality standards, the digital data engineers rely on ArcInfo software's graphical user interface to view the data in the form of a road network map.

Once third party data has been checked for quality, ArcInfo is used to edit and add new geometry and attributes. Its high degree of flexibility in symbolization and the on-the-fly projection capability make it possible for the DMO organization to work with many layers in many different projections simultaneously. For example, a digital data engineer can easily move between different layers, editing a street sign in one screen and quickly toggling to another screen to check the geospatial accuracy of a particular road segment or link.

The traditional data sources, paper maps and raster imagery, must be digitized and formatted appropriately for integration into NAVTECH Maps. The company's geographers use ArcInfo to manage the digitization of these sources and then utilize ArcInfo software's functionality to convert the data into different formats.

Mile by Mile, Layer by Layer

Mile by mile, layer by layer, the maps are built, checked, and rechecked regularly. Armed with a battery of high-tech tools, including differential GPS equipment, to ensure accurate positioning to an absolute five-meter accuracy standard, field analysts literally drive the roads to verify in excess of 150 attributes per road segment. More than 400 field analysts worldwide contribute to this mapping process by driving and scrutinizing millions of miles of roadway every year. The field analysts are an important part of the DMO organization because they are key to building maps to reflect the "reality of the roads." The attributes they verify include turn restrictions (legal, logical, and physical), the functional class of the road (super highway, feeder road, local street), gates, and tollbooths, etc.

Once attributes have been verified, any changes are entered into the database and field-tested again via ArcView software. Field analysts then add another layer of data by geo-coding and linking points of interest (POIs) to the road geometry. POIs include airports, hotels, tourist attractions, gas stations, parks, recreation centers, and ATMs.

For more information, contact Laura Richey, Navigation Technologies (tel.: 312-894-7127, e-mail: lrichey@chi.navtech.com), or visit www.navtech.com.