FMASK

The software called Fmask (Function of mask) is used for automated clouds, cloud shadows, snow, and water masking for Landsats 4-8 and Sentinel 2 images (Qiu et al., 2019). More info regarding the software can be found in its original repository https://github.com/GERSL/Fmask .

BDC uses FMask version 4.2 to generate cloud masks for its Landsat-8 and Sentinel-2 Image Collections, while for it Data Cubes the FMASK band is generated by compositing the existent Image Collection FMASK bands. The following table demonstrates each class pixel value:

FMASK

Class

Pixel value

Clear Land

0

Clear Water

1

Cloud Shadow

2

Snow

3

Cloud

4

No Data

255

References

  • Qiu, S., Zhu, Z. He, B. Fmask 4.0: Improved cloud and cloud shadow detection in Landsats 4–8 and Sentinel-2 imagery. Remote Sensing of Environment 231 (2019).