PUNCHData object

Concept

The PUNCHData object provides a layer atop a typical NDCube object for PUNCH-specific functions. The object includes a primary data array, a WCS describing that data, metadata, and an uncertainty array describing that primary data. Data can be loaded either through this particular object, or through standard FITS readers.

Uncertainty

The uncertainty is stored within the PUNCHData object as a floating-point value from 0-1, describing the relative uncertainty of that pixel - 0 being complete certainty and 1 being complete uncertainty. When written to file, these are stored as 8-bit integer values using the HDU scaling feature. Most FITS readers (AstroPy tested) will reconstitute these to the original range of 0-1.