There are four critical principles that need to guide the development of the NSDI (after Dertouzos, 1991): availability, ease of use, flexibility, and a foundation for other activities.
The NSDI is a national strategy and is not designed to serve the interests of one level of government, one sector in society, or one geographical area. The data should be available through public networks that have maximum user capacity or other media (such as CD-ROM).
Weiser (1991) notes that ''the most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it." New generations of computer appliances and standard software will help to take the use of spatial data from the hands of the technical specialists. Accessing spatial data should become as easy as turning on a light switch: the complexity of networks, standards, and data base structures should be transparent to the user.
The NSDI cannot be dependent on the technology, data, or organizational structures of today; it must be able to anticipate and manage growth. It must cater to the needs of many different types of users and incorporate many types of data. If the potential dissemination of spatial data is to be realized, for example, then communication networks must be capable of handling a wide range of transmission speeds to accommodate everything from simple text to four dimensional animation.
The infrastructure is not an end in itself but the means of realizing the value of spatial information. Its purpose is to foster and not to control new applications, services, and industries.