Valid-pixel expression
The arithmetic expression defines the pixels which are valid for processing. Pixels which are not valid will be
marked as no-data in the
target product. For Landsat 8 no default expression is provided. There are multiple way of doing defining an
expression. Usually one would want to discriminate between land and water.
The expression depends on how the landsat reader is configured.
By default the values are radiances.
near_infrared > 0 && near_infrared < 25
If you have switched to reflectances, the following should work.
near_infrared > 0 && near_infrared < 0.1
The exact values might need to be adjusted.
Alternatively, Idepix can be used for preprocessing and adding a land/water mask, or an elevation band can
be added and based on the elevation value land and water can be discriminated. Or the land-sea mask operator
can be used.