SLC-off Gap Mask

Band-specific gap mask files are included with every Scan Line Corrector (SLC)-off standard data product. These ancillary data allow users 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.

Figure 1. Sample SLC-Off to SLC-On gap mask

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 as listed below.

Value	Meaning
0	No data (data were missing in the original SLC-off scene)
1	Populated data (data were present in the original SLC-off scene)

Gap mask files may not be included in older SLC-off scenes that have not been recently processed. You can create gap mask file by reviewing the information provided on http://landsat.usgs.gov/gap_mask_files_are_not_provided_can_I_create_my_own.php