Landsat Missions

What is the Saturation Bits parameter in the metadata file?

You are here

Question:

What is the Saturation Bits parameter in the metadata file?

Answer:

A new parameter in the Landsat Level-1 product metadata (MTL.txt) file indicates the presence of radiometric saturation for each band in every Landsat scene:

  • SATURATION_BAND_1 = "Y"
  • SATURATION_BAND_2 = "Y"
  • SATURATION_BAND_3 = "Y"
  • SATURATION_BAND_4 = "Y"
  • SATURATION_BAND_5 = "Y"
  • SATURATION_BAND_6_VCID_1 = "Y"
  • SATURATION_BAND_6_VCID_2 = "Y"
  • SATURATION_BAND_7 = "Y"
  • SATURATION_BAND_8 = "N"

Related to this parameter, the Quality Assessment (QA) band for Landsat 4-5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) contains Bits 2 and 3 that represent how many bands contain saturated pixels:

  • 00:    No bands contain saturation
  • 01:     1 to 2 bands contain saturation
  • 10:     3 to 4 bands contain saturation
  • 11:     5 or more bands contain saturation

The saturation information provided in the MTL file and the QA band are simply an overview of saturation and do not provide band-specific saturation information at the pixel level. Pixel saturation is common for TM and ETM+ (particularly in the visible bands). Digital numbers (DN) of 255 are reserved for designating saturated pixels in TM and ETM+. Pixels surrounding those with DN values of 255 are also affected by saturation.

Features likely to cause saturation include clouds, snow/ice, barren soil, and white sand. If band-specific pixel saturation is a concern for a specific application, the DN of the Landsat Level-1 data product should be used as confirmation.  

About

Landsat represents the world's longest continuously acquired collection of space-based moderate-resolution land remote sensing data. Four decades of imagery provides a unique resource for those who work in agriculture, geology, forestry, regional planning, education, mapping, and global change research. Landsat images are also invaluable for emergency response and disaster relief.

 

Contact Us

Landsat Updates

The Landsat Update is an informal communication tool, prepared periodically and distributed electronically to USGS Landsat partners, to provide information about Landsat activities and related topics of interest.

Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://landsat.usgs.gov
Page Contact Information: Ask Landsat
Page Last Modified: 06/22/17 05:09 pm
Sitemap