|Landsat 8 OLI Collection 1 Quality Assessment (QA) Band example|
Landsat Level-1 Quality Assessment (QA) bands are a helpful resource for evaluating the overall usefulness of a Landsat pixel. Each pixel in the QA band contains a decimal value that represents bit-packed combinations of surface, atmospheric, and sensor conditions that can affect the individual pixel quality. The Level-1 QA bands are 16-bit files in GeoTIFF format which require robust image processing software.
To simplify the "unpacking" of the QA band information, the USGS developed the Landsat QA Tools, which were derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) Land Data Operational Product Evaluation (LDOPE) Toolbox. The Landsat QA Tools originally supported Landsat data in Hierarchical Data Format (HDF), similar to MODIS data. However, the USGS has moved away from Landsat HDF data delivery and toward using GeoTIFF as the standard Landsat data product delivery format, and the Landsat QA Tools needed to be changed accordingly. The source code for the original versions of the Landsat QA Tools is available on GitHub.
When the Landsat QA Tools were updated to support GeoTIFF file formats, they were only applicable to Landsat 8 Operational Land Imager (OLI) Pre-Collection Level-1 data since they were the only Landsat data with QA bands. Today, Landsat Collection 1 Level-1 data include QA bands for Landsat 4-5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and an altered QA band for Landsat 8 OLI. The Landsat QA Tools were again updated to support Collection 1 Level-1 QA data. The current versions of the Landsat QA Tools provide support for Landsat 8 OLI Pre-Collection Level-1 QA bands as well as Collection 1 Level-1 QA data.
Download Landsat QA Tools (.zip - 3.7 MB)
Includes: Linux 64-bit and Windows 64-bit executables, a source code directory, a binary directory, and a readme file.
Refer to the Landsat QA Tools User Guide for more information.
No distribution or re-use constraints are associated with the Landsat QA Tools. Users and developers using or modifying these tools should provide credit to the original authors. Please acknowledge the use of these tools, including use of significant code fragments taken from the source code, for example, "Software tools provided by the MODIS land quality assessment group (Roy et al. 2002)".
Roy, D.P., Borak, J.S., Devadiga, S., Wolfe, R.E., Zheng, M., Descloitres, J., 2002, The MODIS Land Product Quality Assessment Approach, Remote Sensing of Environment, 83, 62-76.
Additionally, a user experience with these tools is described in Landsat Surface Reflectance Quality Assurance Extraction (Version 1.7) (J. Jones et al, 2013).
Please use the Contact Us form with any questions regarding the use of the Landsat QA Tools.