Fix landcoverai datamodule (#959)

conf/landcoverai.yaml

@@ -13,7 +13,7 @@ experiment:
     learning_rate: 1e-3
     learning_rate_schedule_patience: 6
     in_channels: 3
-    num_classes: 6
+    num_classes: 5
     num_filters: 256
     ignore_index: null
   datamodule:

torchgeo/datamodules/landcoverai.py

@@ -97,7 +97,7 @@ class LandCoverAIDataModule(pl.LightningDataModule):
         sample["image"] /= 255.0
 
         if "mask" in sample:
-            sample["mask"] = sample["mask"].long() + 1
+            sample["mask"] = sample["mask"].long()
 
         return sample