Landsat Missions

Landsat Quality Assessment ArcGIS Toolbox

Quality Assessment (QA) bands are helpful for evaluating the overall usefulness of a Landsat pixel. Each pixel in the QA band contains an integer value that represents bit-packed combinations of surface, atmospheric, and sensor conditions that can affect the individual pixel quality.

QA bands are currently provided with Landsat Collection 1 Level-1 and Level-2 science products. 

Return to Landsat Quality Assessment Tools Overview

 

This ArcGIS-based toolbox provides functionality to classify and/or extract bit packed values for the QA bands provided with the Landsat Collection 1 Level-1 and Level-2 science products.  The Landsat Quality Assessment (QA) Tools provide the functionality of extracting bit packed values to individual bands for the Landsat Level-1 BQA band only.

Compatible Products

The Landsat QA ArcGIS Toolbox is compatible with all Landsat Collection 1 Level-1 and Landsat Level-2 Science Data QA bands. The table below describes each band’s properties.

A bit-packed band that provides per-pixel information about success or failure of processing and validity of sun glint, view angle, solar angle, polarization, chlorophyll-a, etc.

Band Source Product Description
BQA C1 Level-1 Level-1 Provides information about the quality of surface, atmospheric, and sensor conditions that can affect the overall usefulness of a given pixel
pixel_qa C1 Level-2
Surface Reflectance

 
TOA, SR, SI Populated from C1 Level-1 BQA. Provides information about cloud
confidence, cloud shadow, and snow/ice.
radsat_qa TOA, SR, SI This band is a bit-packed representation of which sensor bands were
saturated during data capture, yielding unusable data
sr_cloud_qa Landsat 4-7 SR (LEDAPS) Provides per-pixel information about dense dark vegetation, cloud,
cloud shadow, adjacency to cloud, snow, and water
sr_aerosol Landsat 8 SR (LaSRC) Provides low-level details about about aerosol factors
that may influence the final product
L2_flags C1 Level-2 Provisional
Aquatic Reflectance
Landsat 8 Aquatic Reflectance Provides per-pixel information about success or failure of processing and validity
of sun glint, view angle, solar angle, polarization, chlorophyll-a, etc.
BQA Level-1 Quality Assessment Band File, LaSRC Land Surface Reflectance Code, LEDAPS Landsat Ecosystem Disturbance Adaptive Processing System, SI Spectral Indices, SR Surface Reflectance, TOA Top of Atmosphere Reflectance

Download Landsat QA ArcGIS Toolbox

The Landsat QA ArcGIS Toolbox provides functionality to classify and/or extract bit packed values for all Collection 1 Level-1 and Level-2 science product QA bands. The use of this tool enhances the applications of interpretation, mapping and applying QA values to all Landsat data products.  

The Landsat QA ArcGIS Toolbox includes the following tools:

Decode QA – decodes bit-packed quality information from Landsat Collection 1 Level-1 and Level-2 QA bands. Unlike bit-unpacking tools, Decode does not generate new bands, but instead builds an attribute table from the input and populates each unique value with its respective classification.

Extract QA Bands – finds all unique values in the QA band, and extracts classes individually, as defined by user input. The tool then writes each class to a new image file, and provides the option to combine all selected classes into a single file.

The Landsat QA ArcGIS Toolbox README file contains installation instructions and all pertinent details for each tool.

Toolbox Caveats

The toolbox was designed using ArcGIS version 10.4.1 and Python version 2.7.10. The functionality of the toolbox cannot be guaranteed for previous software versions, and cross-compatibility of newer and future ArcGIS and Python releases are subject to vendor discretion.  Other caveats include:

  • Input data must be in GeoTIFF (.tif), binary (.img), or other single-band raster format supported by ArcGIS.
  • Input data must be stored in integer format; any float, double, or complex data types are not supported.
  • Any band with values outside of the supported range will not process.
  • If using non-standard (i.e., user modified) file naming conventions, the tool may not correctly identify the band type, which may result in incorrect output products. Ensure the “sensor” and “band” categories are set accordingly.

 

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.