URI: http://www.qualityml.org/1.0/measure/NodataAreas
Name: Nodata areas
Alternative names:  
Definition:

This quality measure indicates if there is absence of data for some reason that made impossible to get data in this area. In the case that the measure is provided as a pixel level quality, the resulting parameters are presented in the form of a data mask.

Parameters: The "reason" provides the reason the value is marked as nodata. Possible values are "anomalous", "not acquired", "unknown value" etc.
Source: A3C
Classes: Completeness
Further information: Typically used in imagery to mark pixels that has a value that does not represent a correct measurement. Can be reported as a boolean per pixel or a percentage of "nodata" pixels in an scene.