Building the National Map.

The U.S. Geological Survey announced its plan for the National Map in the spring of 2001. The proposal included the mission for the map to be a continuously maintained database of geographic information for the entire country, available to the public through the Internet. Now, in 2004, users can log on to, load the National Map Viewer and access a vast amount of data. "The National Map has something for every place in the country," said Mark DeMulder, the acting chief scientist for geography at the USGS.

The National Map's data is divided into eight themes: digital orthorectified imagery, elevation, geographic names, land cover information, and vector data for hydrography, transportation, boundary, and structural features. Data layers for many parts of the country on the National Map are not currently available in high resolution, but the USGS hopes to further the progression of the map in the coming year.

President George W. Bush has proposed $118.9 million for the USGS in the 2005 fiscal year budget-almost $10 million less than the 2004 budget. Much of this decrease is due to an internal restructuring of the USGS geography workforce. If the 2005 budget proposal is passed by the legislature, the appropriated partnership funding, which is sent to federal, state, local and private organizations collaborating with the USGS on the National Map, will be decreased by $1.9 million.

Still, the National Map remains one of the four priorities of the USGS, and approximately $9 million is projected for its partnership funding in 2005. The USGS partners with federal, state, local and private organizations, usually through cost-sharing arrangements, to foster the development of data for the map. Currently, more than 150 partners' datasets are accessible on the National Map.

While in the process of developing the National Map, the USGS wants to assure the surveying community of the map's quality. "When we've spoken with surveyors in the past about where we're heading with the National Map, [their concerns] have to do with data quality and certification," DeMulder said. In the 20th century the topographic maps published by the USGS always carried a statement verifying that the map had met the agency's accuracy standards. "The National Map is digital," DeMulder said, "but we're still holding true to certifying the quality of data that goes into it. Users know they can trust it because it's got the USGS name." While some aspects of the technical certification process still need to be delineated, the USGS promises to uphold its standard of quality. According to Curt Sumner, LS, executive director of the American Congress on Surveying and Mapping (ACSM), no formal agreement currently exists between the ACSM and the USGS. Instead, the two agencies have an ongoing dialogue that includes discussion of the National Map. Through this, the ACSM provides the surveying community's perspectives on the development and practical uses of the National Map.

Data layers displayed through the National Map Viewer are drawn from USGS, state and local government, and private sector sources. Partnerships for data sharing and maintenance ensure access to current information and help to minimize redundant data collection and updating. Users can select and display unique combinations of data that meet their individual needs. (Dover, Del.)

Coordinating the National Map's Data

Since all of the information available on the National Map is in the public domain, proprietary issues of data ownership have been a concern. To work through these issues and continue developing the National Map, the USGS strengthened its relationships with other federal agencies. The coordination of geospatial data, according to Barb Ryan, associate director of geography at the USGS, "is a gigantic job. But we've been quite happy the last year [2003] with what's been done." The five key agencies associated with the National Map are the Census Bureau, the Bureau of Land Management (BLM), the National Oceanic and Atmospheric Administration (NOAA) and the National Geospatial-Intelligence Agency (NGA).

The Census Bureau collects transportation data for the National Map that shows the correct geography of roads and other transportation infrastructure. The BLM coordinates cadastral information with the National Map through the National Integrated Land System (NILS). NOAA supplies land cover data for coastal areas of the country. The NGA provides imagery for 133 designated urban areas.

In addition, the USGS has signed Memoranda of Understanding with the International City/County Management Association (ICMA), the National States Geographic Information Council (NSGIC) and the National Association of Counties (NACo). These three agreements allow for future cooperation among the organizations and the USGS to promote the National Map. (For more specifics on the memoranda, visit

The National Map's Timeline

The timeline for a project as vast as the National Map is hard to define. According to Ryan,"We [the USGS] have good national coverages for all of the key data layers in the National Map. Now we're drilling into selected areas of the country for higher resolution data." This is evident in a few of the data themes of the map.

For example, in the hydrography layer, the scale of the National Map is currently 1:100,000. The USGS is halfway done with improving that to 1:24,000. In some parts of New England, the scale of the hydrography layer is 1:5000. Also, with the help of the NGA, the orthoimagery data for the 133 designated urban areas of the country has already been collected in more than 45 cities.

When asked how soon the National Map's data will be available in high resolution everywhere in the country, Ryan responded, "That's probably a 10-year path." But please take note: the USGS will concentrate first on improving the National Map in areas where their state, local and private partners are located. People who want to improve the National Map's data in their area can help by promoting state and local partnerships with the USGS.

The National Map Corps

Interested in providing information for the "structures" theme of the National Map? You are invited to participate now. Morgan Bearden, the coordinator for the National Map Corps, explains that volunteers using consumer-grade handheld GPS units provide the USGS with the coordinates and a brief explanation of each feature recorded. Structures, which were traditionally known as "˜landscape-worthy,' include features such as noteworthy buildings, schools, hospitals, etc.

In pre-digital days, Bearden said, "Volunteers annotated paper maps, and it might be a very long time until the paper maps were revised and printed." The online National Map will now make the volunteers' updated information available within days or a few short weeks. "The hope [for the National Map] is that everyone who has access to a computer will be able to see this information," Bearden said. And, of course, users will be able to print the map with the themes and information they are interested in.

People interested in volunteering for the National Map Corps can send an E-mail to The National Map Corps currently consists of approximately 2,500 volunteers from all over the country.

New Features in the National Map Viewer

Viewers Consolidated

Previously, four viewers contained all the features and functions needed to view, print and download data from the National Map. Now all these features and functions, plus new ones, are available in just two viewers. The National Map Viewer is the primary viewer and the Seamless Data Distribution System viewer provides enhanced download capabilities.

Updated GNIS Query

The GNIS Find Place tool now allows reporting of query results from the Geographic Names Information System (GNIS) within the National Map Viewer. Users can now zoom to the selected feature in the viewer and view the selected feature as a Digital Orthophoto Quadrangle (DOQ) or a Digital Raster Graphic (DRG). The query results page reports basic information on the selected feature with links to more information.

Updated Download Capability

The download page now allows downloading of USGS image-based data layers (raster data) via a linkage to the USGS Seamless Data Distribution System. Users can now download high-resolution urban orthoimagery, National Elevation Data (NED), and the National Land Cover Dataset (NLCD) when these data layers are available and visible in the viewer.

Improved Availability and Performance

The viewing and catalog system has seen recent improvements in availability and performance. Requests for new maps should be processed more efficiently with improved response times.

These four improvements were added online in February 2004.

Source: The National Map "In the News!"