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I'm using TIMESAT for time-series analysis and Landsat 7-8 Collection 1 images. Within this process I would like to use Landsat pixel quality band for assigning reliability degrees to the pixels using the pixel QA band.

When using CFMask Band the range is easily defined (0 clear; 1 water;2 cloud shadow; 3 snow; 4 cloud). But when I try to use the Pixel QA band the pixel values were different than the values for interpretation given at https://landsat.usgs.gov/landsat-surface-reflectance-quality-assessment.

I have the opportunity to use QGIS, ArcGIS and ENVI for image processing.

How I can use or process the pixel QA band?

  • @Luke do you know a tutorial or a resource that can help me for the bitwise operations that you've mentioned? – Ayda Aktas May 24 '17 at 9:32
  • You need to use bitwise operations to extract the appropriate bit. If you can edit your question and specify what software you have available to preprocess the pixel_qa band, you might get an answer. – user2856 May 24 '17 at 9:33
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Below you'll find the documentation of Landsat 8 SR Code:

https://landsat.usgs.gov/sites/default/files/documents/lasrc_product_guide.pdf

On the page 19 there is a general table with values already calculated to human-friendly format. Note the detailed table at the page 20 - Landsat's QA is not just about Land/Cloud/Water etc., but it has a way more detailed distinction (that you can obviously group to fit your own needs). Hope it helps you.

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