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.
Left: Sample SLC-Off image; Right: SLC gap mask
(Public domain.)
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
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Sample SLC-Off to SLC-On gap mask
Left: Sample SLC-Off image; Right: SLC gap mask