Accounting for alternation in temporal quality analysis in MapBiomas Brazil

Abstract

Land use and land cover maps are an important resource for understanding interactions between humans and their environment across space and time with current mapping efforts often spanning upwards of 20 years. We present here a new method for a robust assessment of land cover transitions over time and apply this methodology to the yearly MapBiomas land use land cover maps of Brazil spanning 1985–2022. Based on a reference sample of 85,152 points, we find MapBiomas to have limited accuracy as an indicator of yearly land use change, but consistent over the full mapping period. Alternation, a newly defined error component, captures the number of land use transitions a location experiences throughout time. It is the primary reason for differences in estimates of annual change and is 4.6 times more frequent in the MapBiomas product than reference data. Differences in alternations are particularly prevalent in transitions from pasture to savanna and forest classes. The total land use changes detected over the 37 year study period are consistent between the reference data and the MapBiomas classification with 232 million hectares and 252 million hectares, or 27% and 29% of the Brazilian territory respectively.