A Research Agenda for Geographic Information Science at the United States Geological Survey recommended that the focus of the USGS Center of Excellence for Geographic Information Science be on TNM, with key extensions into information access and dissemination, integration of data from multiple sources, and data models and knowledge organization systems (NRC, 2007).
In creating and implementing TNM, the USGS is targeting improvements in data characteristics, such as currency, seamlessness, consistent classification and formatting, variable resolution, completeness, variable positional accuracy, spatial reference systems, standardized content, metadata, and temporal dimensions (USGS, 2001; Cramer and DeMulder, 2009). The data themes in TNM are orthoimagery, elevation, hydrography, geographic names, land cover, transportation, structures, boundaries of government units (such as states and counties), and publicly owned lands (such as national forests and state parks). These data themes were chosen to fulfill a gap and for use for the USGS topographic maps, therefore there are plans to retain data characteristics that are more useful to users of the USGS topographic maps, such as consistent feature identification and clas-sification (NRC, 2007).
The USGS offers several methods for accessing data in TNM. For users seeking to view a data map, a map viewer is available (see http://viewer.nationalmap.gov/viewer) and provides basic Geographic Information System-type (GIS) query and analysis tools. Users can also retrieve national coverage data through interactive and preprocessed methods that can be accessed online, via the map viewer, or physical media. For users that create their own map viewer and that need access to tools and inventoried services, the USGS offers program applications and an online catalog of metadata entries that can be discovered and “harvested” into the Geospatial One-Stop portal. The USGS also has service-level agreements with agencies to provide more advanced Web-based access to national databases.
Perhaps the most fundamental change in TNM approach is the transition from reliance on internal USGS resources for collecting new data to reliance on partners for providing new data (NRC, 2007). These USGS partnerships involve a value-based exchange: In exchange for partners’ data, the USGS provides funding, expertise, data, data models, data-collection software tools, information technology, Web and other data-management services, access to contracts, and access to related management and quality-assurance processes.
TNM resides in a large environment that includes electronic mapping products and services provided by the government, academe, and private industry. In the USGS, there are multiple datasets (see Box 2.1) that could eventually be fed into a larger USGS SDI. In the private sector, the emergence of commercial products, such as Google Earth and Microsoft Bing Maps, has captured the interest of the public and professional users. To remain relevant, the 2007 NRC report A Research Agenda for Geographic Information Science at the United States Geological Survey states that the TNM “must be a trusted [emphasis added] geospatial information source for all of these constituencies,” and that “the measure