Calibration of tropical forest area estimates at coarse spatial resolution with fine resolution data

The interaction between the proportional errors produced by spatial aggregation and the spatial pattern of cover types has been modelled in an operational way at a broad spatial scale. A correction function has been calibrated on the basis of tropical forest maps derived from AVHRR 1 km data for the entire intertropical belt and a non-random sample of-thirteen Landsat TM scenes well-distributed among the main tropical forest regions. The calibration model integrates a measure of the spatial fragmentation of the landscape in a two-step procedure. This calibration procedure improves by 35% the reliability of the retrieval of proportions of cover types by comparison to the AVHRR classifications