In GLC_FCS30, GlobeLand30, and FROM_GLC, cropland had the producer’s accuracies of 88.0%, 88.2%, and 47.7% and user’s accuracies of 83.9%, 88.7%, and 74.7%, respectively. Validation dataset link: 10.5281/zenodo.3551994
The results of this study indicated that GlobeLand30 performed better than the other four datasets including FROM_GLC30, regardless of the cropland area and the spatial location. Specifically, the overall accuracy and kappa coefficient of GlobeLand30 were 79.61% and 0.58, respectively, whereas the overall accuracy and kappa coefficient of FROM_GLC30 were 76.23% and 0.52, respectively.
GlobeLand30 shows that there is little loss of the cropland area but increasing fragmentation of cropland in China. Specifically, the results show that 703 out of 2420 countries experienced both cropland loss and increased fragmentation.
GFSAD30 had an overall accuracy of 91.7%, a producer’s accuracy of 83.4%, and a user’s accuracy of 78.3% using 19,171 validation points. For the different regions (North America, South America, Southeast Asia, Africa, Mongolia, New Zealand, China, Europe, the Middle East, Russia, South Asia, and Australia), the overall accuracy of GFSAD30 varied from 84.5% to 98.3%. Validation dataset link: 10.5067/MEaSUREs/GFSAD/GFSAD30VAL.001
The overall accuracies of GFSAD30 exceeded 94% in Australia and China; the cropland omission errors were 1.2% for Australia and 20% for China. Validation dataset link: 10.5067/MEaSUREs/GFSAD/GFSAD30VAL.001
GFSAD30 had an overall accuracy of 90.8% and a weighted accuracy of 93.8% across all zones based on 3000 validation samples. A comparison of GFSAD30 and GlobeLand30 suggested an overall similarity of 88.8% and a kappa coefficient of 0.7. Training and validation dataset link: https://croplands.org
For the African continent as a whole, GFSAD30 had a weighted overall accuracy of 94.5%, a producer’s accuracy of 85.9% (an omission error of 14.1%), and a user’s accuracy of 68.5% (a commission error of 31.5%). The overall accuracy varied from 90.8% to 96.8% for the different agroecological zones. The similarity between GFSAD30 and GlobeLand30 and FROM_GC was also tested. The results indicated that GFSAD30 matched GlobeLand30 for 77.3% of the cropland samples and matched FROM_GC for 68.8% of the cropland samples. Validation dataset link: 10.5067/MEaSUREs/GFSAD/GFSAD30AFCE.001
GFSAD30 had an overall accuracy of 88.1%, a producer’s accuracy of 81.6% (an omission error of 18.4%), and a user’s accuracy of 76.7% (a commission error of 23.3%). The accuracy varied from 83.2% to 96.4% for the different agroecological zones. Validation dataset link: https://croplands.org/app/ data/search
An accuracy assessment of the GFSAD30 cropland map was performed across 15 regions using a reference dataset containing 19,171 samples. The overall accuracy of this cropland extent map for the world was 91.7%. Validation dataset link: 10.5067/MEaSUREs/GFSAD/GFSAD30VAL.001
The average user’s accuracies for GFSAD30 and GlobeLand30 in the five countries were 73.1% and 79.5%, respectively. The omission and commission errors were about 25% and 7%, respectively, for GFSAD30 and about 29% and 5%, respectively, for GlobeLand30.