FROM-GC: 30 m global cropland extent derived through multisource data integration

We report on a global cropland extent product at 30-m spatial resolution developed with two 30-m global land cover maps(i.e.FROM-GLC,Finer Resolution Observation and Monitoring,Global Land Cover;FROM-GLC=agg)and a 250-m cropland probability map.A common land cover validation sample database was used to determine optimal thresholds of cropland probability in different parts of the world to generate a cropland/noncropland mask according to the classification accuracies for cropland samples.A decision tree was then applied to combine two 250-m cropland masks:one existing mask from the literature and the other produced in this study,with the 30-m global land cover map FROM-GLC-agg.For the smallest difference with country-level cropland area in Food and Agriculture Organization Corporate Statistical(FAOSTAT)database,a final global cropland extent map was composited from the FROM-GLC,FROM-GLC-agg,and two masked crop=land layers.From this map FROM-GC(Global Cropland),we estimated the global cropland areas to be 1533.83 million hectares(Mha)in 2010,which is 6.95 Mha(0.45%)less than the area reported by the Food and Agriculture Organization(FAO)of the United Nations for the year 2010.A country-by=country comparison between the map and the FAOSTAT data showed a linear relationship(FROM-GC=1.05*FAOSTAT-1.2(Mha)with R^(2)=0.97).Africa,South America,Southeastern Asia,and Oceania are the regions with large discrepancies with the FAO survey.