Tropical forest mapping from coarse spatial resolution satellite data: production and accuracy assessment issues

Global to regional datasets from coarse spatial resolution satellite sensors are increasingly becoming available. Land cover and vegetation extent maps are among the terrestrial products derived from such data. Whilst they provide a previously unavailable synoptic view of global situations, accuracy assessment methodological issues are often ignored when creating these digital databases or producing statistics from such sources. This paper looks at how these issues are addressed in the framework of the Joint Research Centre’s TREES (Tropical Ecosystem Environment observation by Satellite) project, initiated to map and monitor the pan-tropical humid forest belt using Advanced Very High Resolution Radiometer (AVHRR) data. The paper shows that without accuracy assessment and a correction procedure, both the thematic legend and statistical data derived from coarse spatial maps can be misleading.