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How is the percentage of cloud cover calculated in a Landsat scene?

The C Function of Mask (CFMask) algorithm is used in Landsat Collection 1 Level-1 data processing. This algorithm provides a full-image “Scene Cloud Cover” estimation of the percentage of cloud cover calculated over an entire Landsat scene.  

Land Cloud Cover, which is also included, is determined by calculating the percentage of clouds over land-only pixels in a scene using a mask that discriminates land from water.

Both cloud cover percentages are listed in the EarthExplorer metadata, as well as in the Landsat Collection 1 Level-1 metadata (MTL.txt) file.

Learn more: Landsat Cloud Cover Assessment Validation Datasets

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