How is the percentage of cloud cover calculated in a Landsat scene?

The C Function of Mask (CFMask) algorithm is used in Landsat Collection 1 Level-1 data processing. This algorithm provides a full-image “Scene Cloud Cover” estimation of the percentage of cloud cover calculated over an entire Landsat scene.  

Land Cloud Cover, which is also included, is determined by calculating the percentage of clouds over land-only pixels in a scene using a mask that discriminates land from water.

Both cloud cover percentages are listed in the EarthExplorer metadata, as well as in the Landsat Collection 1 Level-1 metadata (MTL.txt) file.

Learn more: Landsat Cloud Cover Assessment Validation Datasets

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What are Landsat Collection Tiers?

Landsat Collection Tiers are the inventory structure for Level-1 data products and are based on data quality and level of processing. The tier definition purpose is to support easier identification of suitable scenes for time-series pixel-level analysis, and provide temporary data that are processed immediately upon downlink to be dispensed...

What are Landsat Collections?

In 2016, the USGS reorganized the Landsat archive into a tiered collection. This structure ensures that Landsat Level-1 products provide a consistent archive of known data quality to support time-series analyses and data “stacking”, while controlling continuous improvement of the archive and access to all data as they are acquired. Learn more:...

What are the band designations for the Landsat satellites?

The sensors aboard each of the Landsat satellites were designed to acquire data in different ranges of frequencies along the electromagnetic spectrum ( View Bandpass Wavelengths for all Landsat Sensors ). The Multispectral Scanner (MSS) carried on Landsat 1,2,3,4 and 5 collected data in four ranges (bands); the Thematic Mapper (TM) sensor on...

What is Landsat definitive ephemeris?

Definitive Ephemeris is used for geometrically correcting Landsat 7 data and providing improved accuracy over predicted ephemeris. Learn more (and download DE files): Landsat Definitive Ephemeris

What Landsat data products are available?

There are several Landsat data products that are useful for science applications and land use/land change studies: Landsat Collections Level 1 - Ensures that the data in the Landsat Level-1 archive are consistent in processing and data quality to support time-series analyses and data stacking. Each Level-1 data product includes individual spectral...

What are the processing levels for Landsat Level-1 data?

The table below shows the Landsat Collections Level-1 processing levels: Landsat Level-1 Processing Levels Processing Level Description Terrain Precision Correction (L1TP) Radiometrically calibrated and orthorectified using ground control points (GCPs) and digital elevation model (DEM) data to correct for relief displacement.The highest quality...

What are U.S. Landsat Analysis Ready Data (ARD)?

U.S. Landsat Analysis Ready Data (ARD) are pre-packaged and pre-processed bundles of Landsat data products that make the Landsat archive more accessible and easier to analyze, and reduce the amount of time users spend on data processing for time-series analysis. ARD contains Level-2 products derived from Landsat Collections Level-1 scenes. ARD are...
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Date published: March 24, 2017

New “Landsat Collections” Help Facilitate Land Change Science

Access to consistent high-quality images to study changes on Earth’s surface is getting easier. The USGS Landsat standard (Level-1) product inventory is now structured by data quality and offers improved calibration. Data designated as Tier 1 provide the highest accuracy and can be reliably used to analyze changes to Earth’s surface over time.

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 Example of a cloudless image of the western states in the U.S., composed using Landsat. Courtesy of Mapbox.
November 2, 2016

Example of a cloudless image of the western states in the U.S.

 Example of a cloudless image of the western states in the U.S., composed using Landsat. Courtesy of Mapbox.

Landsat image shows the marine stratus and stratocumulus cloud layer that moved into the San Francisco Bay-Delta
April 15, 2016

Landsat image shows the marine stratus and stratocumulus cloud layer San Francisco Bay-Delta

Landsat image of May 22, 1991 shows the marine stratus and stratocumulus cloud layer that moved into the San Francisco Bay-Delta and Monterey Bay. Several cloud patterns can be seen in this image: the eddy-like spiral to the west of the Golden Gate, the darker linear cloud feature that parallels the coast down to Monterey Bay, and fog funneling from Monterey Bay inland.

Cloudscape in a BLM wilderness study area.
June 15, 2015

Cloudscape in a BLM wilderness study area.

Cloudscape in a BLM wilderness study area. Photo courtesy of BLM.

Large cloud and storm system over Africa, as seen from the International Space Station
February 5, 2008

Satellite view of cumulonimbus cloud over Africa

Satellite view of cumulonimbus cloud over Africa

This picture shows cumulonimbus clouds over Africa photographed from the International Space Station. Cumulonimbus (from the Latin for "puffy" and "dark") clouds form due to vigorous movement of warm and moist unstable air. Rising air currents containing water vapor and varying layers of differing-

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Earth As Art image Von Karman Vortices
July 4, 2002

Von Karman Vortices

As air flows over and around objects in its path, spiraling eddies, known as Von Karman vortices, may form. The vortices in this image were created when prevailing winds sweeping east across the northern Pacific Ocean encountered Alaska's Aleutian Islands.

  • Collection: Earth as Art 2
  • Source: Landsat 7
  • Download: 
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Earth As Art image Whirlpool in the Air
May 1, 2001

Whirlpool in the Air

This image shows a spinning formation of ice, clouds, and low-lying fog off the eastern coast of Greenland.

  • Collection: Earth as Art
  • Source: Landsat 7
  • Scale: 1.7 miles (2.8km)
  • Download: JPG 
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Earth As Art image Aleutian Clouds
June 1, 2000

Aleutian Clouds

These cloud formations were seen over the western Aleutian Islands. Their color variations are probably due to differences in temperature and in the size of water droplets that make up the clouds.

  • Collection: Earth as Art
  • Source: Landsat 7
  • Scale: 2.3 miles (3.7km)
  • Download: 
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Earth As art image Karman Vortices
September 1, 1999

Karman Vortices

Each of these swirling clouds is a result of a meteorological phenomenon known as a Karman vortex. These vortices appeared over Alexander Selkirk Island in the southern Pacific Ocean. Rising precipitously from the surrounding waters, the island's highest point is nearly a mile (1.6 km) above sea level. As wind-driven clouds encounter this obstacle, they flow around it to

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Landsat 8 Image Indicating Scene and Land Cloud Cover

Landsat 8 Image Indicating Scene and Land Cloud Cover

This image is an example for how the CLOUD COVER and the LAND CLOUD COVER scores are indicated in Landsat Collection Level-1 data. 

The metadata for this Landsat 8 scene, acquired of Path 4 Row 53 on April 9, 2019, indicates an overall Scene CLOUD COVER score of 17.07 percent, and a LAND CLOUD COVER score of 18.06. 

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A cloud whose formation is influenced by winds flowing over mountains.

A lenticular cloud over the Tararua Range mountains, New Zealand.

Clouds in the atmosphere - The water cycle

This picture shows a lenticular cloud over the Tararua Range mountains, North Island, New Zealand. What's happening above those mountains? Several clouds are stacked up into one striking lenticular cloud. Normally, air moves much more horizontally than it does vertically. Sometimes, however, such as when

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