What it takes each day to keep Landsat 7 operating smoothly. Hear the stories from inside the L7 Mission Operation Center.
What are Landsat 7 SLC-off Gap Mask files?
Band-specific gap mask files are included with every Landsat 7 Scan Line Corrector (SLC)-off Level-1 data product. These ancillary data identify the location of all pixels affected by the original data gaps in the primary SLC-off scene.
The gap mask is provided as a series of individual band files, in compressed (GZIP) GeoTIFF format.
Sources/Usage: Public Domain. View Media Details
Gap Mask Legend Values:
- green = primary scene
- blue = fill scene 1
- yellow = fill scene 2
- pink = fill scene 3
- red = no data (not filled)
For a standard SLC-off product, the data values contained within the gap mask file are:
- Value of 0 - No data (data were missing in the original SLC-off scene)
- Value of 1 - Populated data (data were present in the original SLC-off scene)
Learn more: Landsat 7 web page
Related Content
Does the Landsat 7 Scan Line Corrector (SLC)-off artifact affect Landsat Collections tier designation?
The Landsat 7 SLC-off artifact does not change how the data are placed into Landsat Collection tiers, as tier classifications are determined by the radiometric and geometric accuracy of each scene. Learn more: Landsat Collections Landsat Data Access
What is Landsat 7 ETM+ SLC-off data?
Landsat 7 ETM+ SLC-off data refers to all Landsat 7 images collected after May 31, 2003, when the Scan Line Corrector (SLC) failed. These products have data gaps, but are still useful and maintain the same radiometric and geometric corrections as data collected prior to the SLC failure. See the Landsat 7 website for information about the SLC-off data products.
Why do Landsat 7 Level-1 products contain two thermal bands?
Landsat 7 acquires thermal data in two bands from one detector in both high (Band 6H) and low (Band 6L) gain. The difference in gain settings is important to different types of studies (i.e., clouds vs. deserts). Aside from the resolution differences and saturation on the high and low ends, the two bands provide the same Digital Numbers (DN) for every pixel. FILE_NAME_BAND_6_VCID_1 (band 61 or 6L)...
What are the _VER.jpg and _VER.txt files that are included with the Landsat MSS and TM data?
The Verify Image (_VER.jpg) and Geometric Verify Report (_VER.txt) files are included with Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) Collection 1 Level-1 scenes that have processed into Tier 1. The Verify Image File displays a colored grid of verification points to represent the accuracy of geometric correction, using cross-correlation techniques to compare the product to the...
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.
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 Level-1 Science Products - Each Level-1 scene includes individual spectral band files, a metadata file, and additional ancillary files. These products cover worldwide scenes. U.S. Landsat Analysis Ready Data (ARD ) - Uses Landsat Collections Level-1 data as input to provide...
What are the best Landsat spectral bands for use in my research?
The Spectral Characteristics Viewer is an interactive tool that can be used to visualize how the bands, or channels, of different satellite sensors measure the intensity of the many wavelengths (colors) of light. This is also known as the relative spectral response (RSR). By overlaying the spectral curves from different features (spectra), one can determine which bands of the selected sensor will...
Daily Operations of Landsat 7
What it takes each day to keep Landsat 7 operating smoothly. Hear the stories from inside the L7 Mission Operation Center.
The Optimist
On the edge of the Kalahari Desert in Namibia, sand dunes are encroaching onto once-fertile lands in the north. Healthy vegetation appears red in this image; in the center, notice the lone red dot. It is the result of a center-pivot irrigation system, evidence that at least one optimistic farmer continues to work the fields despite the approaching sand.
On the edge of the Kalahari Desert in Namibia, sand dunes are encroaching onto once-fertile lands in the north. Healthy vegetation appears red in this image; in the center, notice the lone red dot. It is the result of a center-pivot irrigation system, evidence that at least one optimistic farmer continues to work the fields despite the approaching sand.
Bolivian Deforestation
Once a vast carpet of healthy vegetation, the Amazon rain forest is changing rapidly. This image of Bolivia shows dramatic deforestation in the Amazon Basin. Loggers have cut long paths into the forest, while ranchers have cleared large blocks for their herds. Fanning out from these clear-cut areas are settlements built in radial arrangements of fields and farms.
Once a vast carpet of healthy vegetation, the Amazon rain forest is changing rapidly. This image of Bolivia shows dramatic deforestation in the Amazon Basin. Loggers have cut long paths into the forest, while ranchers have cleared large blocks for their herds. Fanning out from these clear-cut areas are settlements built in radial arrangements of fields and farms.
Parana River Delta
The Parana River delta is a huge forested marshland about 32km northeast of Buenos Aires, Argentina. The area is a very popular tour destination. Guided boat tours can be taken into this vast labyrinth of marsh and trees. The Parana River delta is one of the world's greatest bird-watching destinations.
The Parana River delta is a huge forested marshland about 32km northeast of Buenos Aires, Argentina. The area is a very popular tour destination. Guided boat tours can be taken into this vast labyrinth of marsh and trees. The Parana River delta is one of the world's greatest bird-watching destinations.
Related Content
- FAQ
Does the Landsat 7 Scan Line Corrector (SLC)-off artifact affect Landsat Collections tier designation?
The Landsat 7 SLC-off artifact does not change how the data are placed into Landsat Collection tiers, as tier classifications are determined by the radiometric and geometric accuracy of each scene. Learn more: Landsat Collections Landsat Data Access
What is Landsat 7 ETM+ SLC-off data?
Landsat 7 ETM+ SLC-off data refers to all Landsat 7 images collected after May 31, 2003, when the Scan Line Corrector (SLC) failed. These products have data gaps, but are still useful and maintain the same radiometric and geometric corrections as data collected prior to the SLC failure. See the Landsat 7 website for information about the SLC-off data products.
Why do Landsat 7 Level-1 products contain two thermal bands?
Landsat 7 acquires thermal data in two bands from one detector in both high (Band 6H) and low (Band 6L) gain. The difference in gain settings is important to different types of studies (i.e., clouds vs. deserts). Aside from the resolution differences and saturation on the high and low ends, the two bands provide the same Digital Numbers (DN) for every pixel. FILE_NAME_BAND_6_VCID_1 (band 61 or 6L)...
What are the _VER.jpg and _VER.txt files that are included with the Landsat MSS and TM data?
The Verify Image (_VER.jpg) and Geometric Verify Report (_VER.txt) files are included with Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) Collection 1 Level-1 scenes that have processed into Tier 1. The Verify Image File displays a colored grid of verification points to represent the accuracy of geometric correction, using cross-correlation techniques to compare the product to the...
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.
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 Level-1 Science Products - Each Level-1 scene includes individual spectral band files, a metadata file, and additional ancillary files. These products cover worldwide scenes. U.S. Landsat Analysis Ready Data (ARD ) - Uses Landsat Collections Level-1 data as input to provide...
What are the best Landsat spectral bands for use in my research?
The Spectral Characteristics Viewer is an interactive tool that can be used to visualize how the bands, or channels, of different satellite sensors measure the intensity of the many wavelengths (colors) of light. This is also known as the relative spectral response (RSR). By overlaying the spectral curves from different features (spectra), one can determine which bands of the selected sensor will...
- Multimedia
Daily Operations of Landsat 7
What it takes each day to keep Landsat 7 operating smoothly. Hear the stories from inside the L7 Mission Operation Center.
What it takes each day to keep Landsat 7 operating smoothly. Hear the stories from inside the L7 Mission Operation Center.
The OptimistOn the edge of the Kalahari Desert in Namibia, sand dunes are encroaching onto once-fertile lands in the north. Healthy vegetation appears red in this image; in the center, notice the lone red dot. It is the result of a center-pivot irrigation system, evidence that at least one optimistic farmer continues to work the fields despite the approaching sand.
On the edge of the Kalahari Desert in Namibia, sand dunes are encroaching onto once-fertile lands in the north. Healthy vegetation appears red in this image; in the center, notice the lone red dot. It is the result of a center-pivot irrigation system, evidence that at least one optimistic farmer continues to work the fields despite the approaching sand.
Bolivian DeforestationOnce a vast carpet of healthy vegetation, the Amazon rain forest is changing rapidly. This image of Bolivia shows dramatic deforestation in the Amazon Basin. Loggers have cut long paths into the forest, while ranchers have cleared large blocks for their herds. Fanning out from these clear-cut areas are settlements built in radial arrangements of fields and farms.
Once a vast carpet of healthy vegetation, the Amazon rain forest is changing rapidly. This image of Bolivia shows dramatic deforestation in the Amazon Basin. Loggers have cut long paths into the forest, while ranchers have cleared large blocks for their herds. Fanning out from these clear-cut areas are settlements built in radial arrangements of fields and farms.
Parana River DeltaThe Parana River delta is a huge forested marshland about 32km northeast of Buenos Aires, Argentina. The area is a very popular tour destination. Guided boat tours can be taken into this vast labyrinth of marsh and trees. The Parana River delta is one of the world's greatest bird-watching destinations.
The Parana River delta is a huge forested marshland about 32km northeast of Buenos Aires, Argentina. The area is a very popular tour destination. Guided boat tours can be taken into this vast labyrinth of marsh and trees. The Parana River delta is one of the world's greatest bird-watching destinations.
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