the resolutions at the state or national level). Traditionally, soils data have been collected at the county level. Traffic accidents and crime statistics are collected locally. Incidences of disease data are most useful at the local level. Other possible themes include ZIP code areas, zoning requirements, and traffic flows.

It is evident that a local extended Framework must be defined with the cooperation of city and county officials, and that only those additional themes used for the majority of applications should be incorporated into an extended Framework. To do this, county officials need to be involved in the discussions leading to the definition and establishment of an extended Framework. These discussions should take the form of a nation wide needs assessment which would develop a clear articulation of the content and necessary scale of spatial data required to meet specific objectives and mandates at each level of government. The outcome of this must be a list of themes and their content that can be applied at the local level. This bottom-up approach is in line with the I-Team initiatives advocated by OMB. The committee is encouraged that the National Association of Counties (NACo) began formal cooperation with the FGDC in 1997. This cooperation needs to be continued with specific goals established relating to the definition of an extended Framework.

The starting point of a state or tribal nation extended Framework is also the FGDC’s Framework. Therefore, a state Framework will include geodetic control, orthophoto imagery, elevation, transportation, hydrography, governmental units, and cadastral information. The geodetic control, elevation, and orthophoto imagery layers may be supplemented by the state. Governmental units, a state responsibility that is often delegated to the local level (municipal boundaries, school district boundaries), would probably not receive much additional supplementation except for such features as state legislative district boundaries, state parks, and state forests. Similarly, the cadastral layer augmentation at the

state level might be limited to state-owned lands, however, some states such as Maryland maintain tax parcels on a statewide basis.

A tribal nation Framework would differ from state Frameworks in several ways. Among the most important is the complex pattern of property ownership on many reservations, with some property held by the community, some by individuals, and some by non-tribal owners. This makes distribution of income from tribal assets (e.g., oil and gas lease income) particularly difficult. The involvement of the federal Bureau of Indian Affairs adds an additional bureaucratic layer that makes geospatial data management somewhat more difficult.

One major difference between a state and tribal nation Framework and the FGDC Framework is the definition of the content of the transportation layer. For example, at the state level linear transportation features such as roads may still be defined by their centerlines (as in the federal contribution to the NSDI), but they may carry additional information (county limits, mileage, snow removal, signage placement, and other maintenance responsibilities). New technologies, such as GPS-equipped vans, roadway sensors, high-resolution (1-meter) remote sensing, and digital photogrammetry, are revolutionizing the availability of accurate geospatial data in the transportation layer. In most states, departments of transportation are major agencies that handle such services as driver licensing, vehicle title and registration, interstate commerce taxes, in addition to the features listed above. As the spatial dimensions of these layers become increasingly in demand, the states will find that this information should be made compatible with the SSDI.

Hydrography is also of major concern at the state level, and includes navigation, energy, and recreational users as well as point and non-point pollution sources. There are also regional concerns over water rights and quality. Watersheds often contain several local jurisdictions, and therefore the state must assume responsibility for data relating to drainage basins. The state that handles fishing licenses typically designates public access points to lakes and waterways, patrols open water, and plays a major role in the mitigation of natural disasters involving its watercourses.

Even though it is highly recommended that NAD 83 and NAVD 88 and latitude and longitude be used as the bases of a