Landsat Collection 2 Quality Assessment Bands
Landsat Collection 2 Level-1 and Level-2 Quality Assessment (QA) bands provide useful information to users wanting to optimize the value of pixels as a first level indicator of certain conditions within Landsat data.
Return to Landsat Collection 2 information
Collection 2 Level-1 products are delivered with a Pixel Quality Assessment Band (QA_Pixel) and a Radiometric Saturation Quality Assessment Band (QA_RADSAT). Collection 2 Level-2 products (Landsats 4-8 only) include the Level-1 QA bands as well as a surface reflectance aerosol QA Band for Landsat 8 (SR_QA_AEROSOL), a surface reflectance cloud quality assessment band (SR_Cloud_QA) for Landsat 4-7, and a surface temperature QA Band (ST_QA) for Landsat 4-8 that provide consistent QA information between products.
Access the Documents Section below for additional technical details about the QA files.
Landsat Collection 2 Level-1 and Level-2 QA Bands
Pixel Quality Assessment Band (QA_PIXEL)
QA_PIXEL Band file contains quality statistics gathered from the image data and cloud mask information for the scene. The table below shows the Landsat 8-9 Collection 2 Quality Assessment pixel (QA_PIXEL) Value Interpretations. The Level 2 Pixel Quality Assessment band (QA_PIXEL) includes the information from the Level 1 Quality Assessment (QA_PIXEL) band which is carried through unchanged into Level 2 product package.
The table below displays the Landsat 8 and Landsat 9 Pixel QA_PIXEL Value Interpretations. More details about the QA_Pixel values can be found in the Landsat 8-9 Collection 2 Level 2 Science Product Guide.
* In February 2021, an issue has been discovered in the Pixel QA ‘clear bit’ (bit 6) for Landsat 4-7 scenes over water. Please visit the Landsat Collection 2 Known Issues page for more details about this issue.
Radiometric Saturation Quality Assessment band (QA_RADSAT)
The QA_RADSAT band indicates which sensor band(s) are saturated. The terrain occlusion bit is set when the desired terrain is not visible from the sensor due to intervening terrain (Landsat 8-9 only) and the dropped pixel bit is set when a pixel is dropped (Landsat 1-7).
Landsat Collection 2 Level-2 QA Bands
Surface Reflectance Quality Assessment Band (SR_QA_AEROSOL) – Landsat 8/9
The SR_QA_AEROSOL band is delivered with the Landsat 8/9 Surface Reflectance product to provide low-level detail about the factors that may have influenced the final product result and shows whether the aerosol was a valid retrieval, or if it was interpolated from the surrounding grid points.
Surface Reflectance Cloud Quality Assessment Band (SR_Cloud_QA) – Landsat 4-7
The SR Cloud QA file shares some of the data artifacts and land surface classification indications as the QA Band file. The SR Cloud QA file is generated using Level 2 LEDAPS, unlike the QA_Pixel Band file generated at Level 1
Surface Temperature Quality Assessment Band (ST_QA)
The ST QA file indicates uncertainty about the temperatures given in the ST band file. The ST QA file is generated using uncertainty values and distance to cloud values. Higher numbers indicate greater uncertainty. This file is not included in the product when an SR-only product is generated.
Documents
Collection 2 Level-1 Documents
- Landsat 8-9 OLI/TIRS Collection 2 Level 1 Data Format Control Book
- Landsat 7 ETM+ Collection 2 Level 1 Data Format Control Book
- Landsat 4-5 TM Collection 2 Level 1 Data Format Control Book
- Landsat 1-5 MSS Collection 2 Level 1 Data Format Control Book
Collection 2 Level-2 Documents