An analysis of the IGBP global land-cover characterization process

The International Geosphere Biosphere Programme (IGBP) has called for the d evelopment of improved global land-cover data for use in increasingly sophi sticated global environmental models. To meet this need, the staff of the U .S. Geological Survey and the University of Nebraska-Lincoln developed and applied a global land-cover characterization methodology using 1992-1993 1- km resolution Advanced Very High Resolution Radiometer (AVHRR) and other sp atial data. The methodology based on unsupervised classification with exten sive postclassification refinement, yielded a multi-layer database consisti ng of eight land-cover data sets, descriptive attributes, and source data. An independent IGBP accuracy assessment reports a global accuracy of 73.5 p ercent, and continental results vary from 63 percent to 83 percent. Althoug h data quality, methodology, interpreter performance, and logistics affecte d the results, significant problems were associated with the relationship b etween AVHRR data and fine-scale, spectrally similar land-cover patterns in complex natural or disturbed landscapes.