Why are negative values observed over water in some Landsat Surface Reflectance products?

Landsat atmospheric correction and surface reflectance retrieval algorithms are not ideal for water bodies due to the inherently low surface reflectance of water. Similarly, surface reflectance values greater than 1.0 can be encountered over bright targets such as snow and playas. These are known computational artifacts in the Landsat surface reflectance products.  

Learn more Landsat Surface Reflectance

 

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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:...

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-...

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...

How do I search for and download ascending (nighttime) Landsat scenes?

Ascending (nighttime) WRS-2 Path/Row numbers are different from descending (daytime) Path/Rows. Cloud cover values for Landsat night scenes will always be zero. If you know the daytime path/row or coordinates and want to know the nighttime path/row, use the WRS-2 Path/Row to Latitude/Longitude Converter . Use EarthExplorer to search using path/row...

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...

What are some known issues that users might find in Landsat data?

A number of artifacts and anomalies can happen to any remote sensing data. Banding, dropped scan lines, and detector failures are only a few of the anomalies that can be seen in Landsat data. Go to Landsat Known Issues for details about anomalies that have been discovered and investigated.
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Landsat satellite image of Tampa Bay, Florida
August 11, 2018

Tampa Bay, Florida (Landsat satellite image)

Landsat image of Tampa Bay, Florida, taken on March 22, 1991. Landsat TM satellite imagery Bands 7, 2, and 1; processed at Center for Coastal Geology, St. Petersburg, Florida.

Attribution: Water Resources
December 31, 2017

Landsat Collections

Landsat Collections: Providing a Stable Environmental Record for Time Series Analysis

This video introduces the new U.S. Geological Survey (USGS) Landsat Collection 1 inventory structure. Collection 1 required the reprocessing of all archived Landsat data to achieve radiometric and geometric consistency of Level-1 products through time and across all Landsat sensors

September 19, 2017

Landsat Collections — What are Tiers?

This is the third video in a series describing the new U.S. Geological Survey (USGS) Landsat Collection 1 inventory structure. Collection 1 required the reprocessing of all archived Landsat data to achieve radiometric and geometric consistency of Level-1 products through time and across all Landsat sensors. This video explains how Landsat Collection Level-1 data products

June 30, 2017

Landsat Collections - RMSE

Landsat Collections: Providing a Stable Environment Record for Time Series Analysis

This is the second of a three-part video series describing the new U.S. Geological Survey (USGS) Landsat Collection 1 inventory structure. Collection 1 required the reprocessing of all archived Landsat data to achieve radiometric and geometric consistency of Level-1 products through

Earth As Art image Ice Stars
August 4, 2002

Ice Stars

Like distant galaxies amid clouds of interstellar dust, chunks of sea ice drift through graceful swirls of grease ice in the frigid waters of Foxe Basin near Baffin Island in the Canadian Arctic. Sea ice often begins as grease ice, a soupy slick of tiny ice crystals on the ocean's surface. As the temperature drops, grease ice thickens and coalesces into slabs of more solid

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Aerial view of an island with clouds floating above it, with distinctive land features like mountains and agriculture.
December 26, 2000

Landsat satellite image of Kauaʻi

This image was acquired on December 26, 2000, by the Enhanced Thematic Mapper plus instrument aboard NASA’s Landsat 7 satellite.

Cape Town, False Bay, South Africa
December 31, 1978

Cape Town, False Bay, South Africa Landsat 3 1978

This image is a portion of a Landsat 3 scene acquired December 1, 1978. The city of Cape Town can be seen in the upper left quadrant, and False Bay is along the bottom part of the image.  The right side of the image shows a number of the many nature  and wilderness reserves in the area.