Using multisource data in global land-cover characterization: concepts, requirements, and methods

Global land-cover data are needed as baseline information for global change research. Multisource data, both coarse resolution satellite data and ancillary data, were used to produce a land-cover characteristics database for the conterqinous United States. Ancillary data, including elevation and ecological region data sets, were critical to the development, refinement, and information content of each class in the database. They contributed essential evidence for labeling and refining land-cover classes where differing types were represented by single spectral-temporal signatures. The characterization process can be expanded to a global effort depending on (1) the availability of global satellite coverage, (2) the quality and availability of ancillary data, and (3) the evolution of more sophisticated data visualization and analysis techniques.