Abstract
M.Inf.
Users of geographic information systems (GIS) are often faced with a challenge with regard to identification, location and overall access to digital data used in the application of GIS. The selection of the appropriate data from the large volumes available, also gaining access to available data and the establishment of the distribution of data from one central source are necessary tasks in order to improve the dissemination of GIS data. However, these are difficult tasks due to many users being unaware of the full range of available digital GIS data. A mechanism that could assist in improving access to digital GIS data is the Webbased GIS clearinghouse. This study was initiated to determine the requirements of GIS clearinghouses for optimum accessibility to digital GIS data. A literature study was conducted to investigate the nature of data that is used in GIS clearinghouses, the current trends in GIS data on the Web and the unique characteristics of the Web that can increase accessibility to digital GIS data. A selection of clearinghouses was made and these were evaluated in order to determine variables that can be translated into criteria from which a model for the evaluation of GIS clearinghouses could be established. This model can act as a working document or check-list for users to evaluate GIS clearinghouses, or for designers to create new or improve existing GIS clearinghouses.