ABSTRACT
In recent years , roughly dating from the popularizing of the Internet beginning in 1993, there has been rapid and massive growth in the use of electronic networks for sharing geospatial data. Today, it is possible to find a vast resource of geospatial data, along with such derivative products as maps, all distributed over the tens of millions of servers connected to the Internet, and accessed using simple and widely available tools. Many governments have developed digital clearinghouses and warehouses of geospatial data as part of efforts to sponsor and build spatial data infrastructures (see, for example, the National Geospatial Data Clearinghouse of the Federal Geographic Data Committee, and its proposed Geospatial Data One-Stop, https://www.fgdc.gov" xmlns:xlink="https://www.w3.org/1999/xlink">https://www.fgdc.gov). This process is evident at many scales, from cities and counties to states, nations, and the globe (Masser 1998, National Research Council 1993, Rhind 1997). The totality of geospatial data resources available through some servers exceeds one terabyte (TB), and one might guess that the total global geospatial data resource available in digital form through the network is now of the order of one petabyte (1015 bytes).
