substantial duplication of effort, as virtually identical digital products appear from different agencies to satisfy their often very specific needs. The costs of creating and maintaining digital spatial data are high, so it is particularly important that data created at considerable cost and effort be shareable, that costly data collection not be duplicated, and that the collected data be fully utilized to realize all of their potential benefits.
The next decade will see rapid and large-scale investment in communications technology as the nation moves to exploit the full potential of the information age. Recent actions by the federal government, including the passage of the act calling for a National Information Infrastructure (NII), as well as announced plans for private and public investment, make it clear that within a few years an unprecedented capability will exist for sharing of data along ''electronic superhighways.'' Investment in digital communications technology has been likened to the national investment in the interstate highway network in the 1950s and 1960s, which spawned a major restructuring of U.S. society. Already some 10 million users of the Internet research network communicate nationally and internationally at megabit speeds. Many are predicting that within the next 10 years we will see a similar development in the consumer marketplace.
The high-speed communication networks will be essential for widespread access and sharing of spatial data. Spatial data tend to be voluminous, and sharing has traditionally been difficult at the communication speeds and bandwidths that were available in the past. Standards were often absent, or confusing at best, and it was often more cost-effective to communicate by mailing a paper map and redigitizing it rather than confront the problems of digital format conversion. In the last few years the research community has begun to develop effective methods for describing data quality and other aspects of data that potential users must know if they are to be able to assess the potential value of someone else's spatial data for their own use.
A major challenge over the next decade will be to increase the use of spatially referenced data to support a wide variety of decisions at all levels of society. Using an effective, efficient, and widely accessible NII, spatial data could be readily transported and easily integrated both thematically (e.g., across environmental, economic, and institutional data bases) and hierarchically (e.g., from local to national and eventually to global levels). Transparent access to myriad data bases could provide the information for countless applications, e.g., facility management, real estate transactions, taxation, land-use planning, transportation, emergency services, environmental assessment and monitoring, and research. Work on these applica