Land cover mapping is a complex task, requiring careful research of interactions between the satellite sensor, atmospheric conditions, elements of earth ecosystems and use of expert knowledge and ancillary materials needed for validation and calibration. This study finds that the USGS global land cover database is an innovative and convenient mapping framework, from which a new, and different, global forest cover map is derived. The techniques used for deriving the FAO forest cover has worked effectively when regional stratification is properly adopted, providing a useful tool and product for the FRA2000 global assessment. Factors affecting quality of the derived global forest cover map include misclassification errors from the USGS product, errors of translation to the FAO legend, data quality problems, and accuracy of the linear unmixing approach.
