level of aggregation required by the first agency could not be achieved by the data collection capabilities of the second agency; and (3) the data could not be collected in the time frame required by the other agency.
With the advent of GIS, an extremely versatile, efficient tool has become available for manipulating spatial data. The diverse types of GIS applications have driven the need for more timely and accurate spatial data, particularly in digital form. This also has created the need data base products that are adapatable to rapidly changing user needs.
As federal agencies discovered the value of using GIS for storing and manipulating spatial data, budgets were constructed to purchase such equipment and to collect the needed data in digital form. Early efforts resulted in a myriad of data formats, standards, and processing algorithms. In effect, each federal agency repeated what it had done with paper products, only in digital form.
The cost (in staff hours) of collecting spatial data in digital form is projected to be half the cost of collecting data by manual methods for the generation of individual products (DMA, 1991). Once collected, though, the value of such digital data increases manyfold. The ability to extract subsets, generalize, and thin the data; increase its densification; or merge (fuse) it with other spatial data has created such exciting applications as emergency response (911) location systems, integrated land use/transportation planning models, battlefield management systems, crop rotation forecasts, and environmental impact assessments.
While reviewing the spatial data activities of several federal agencies, the MSC recognized a number of general issues and impediments that need to be resolved to build a more robust NSDI.
ISSUE 1: There is no agreed-upon national vision of the NSDI nor is there an apparatus to implement it. Consequently, there is no national policy covering spatial data nor is there a national organization or agency with the charter, authority, and vision to provide leadership of the nation's spatial data collection, use, and exchange.
Each federal agency with a responsibility for collecting spatial data traces this responsibility to the fulfillment of its primary mission. For example, the spatial data collected by the USGS satisfy its requirement to