MISSING_CONSTANT Meaning/Documentation

[agc5]

Hello,

Can you point me to where I can find documentation regarding what the value of MISSING_CONSTANT represents? I have checked the RDR SIS, and didn't see anything. It's likely I'm overlooking something. 

For example, the LDRM_40N_1000M.IMG file shows a MISSING_CONSTANT value of -32768. Is this value meant to fix the OFFSET value? 

Thank you.

 

 

[Susie Slavney]

MISSING_CONSTANT is the value used to indicate that no actual data value exists; that is, the data value is missing. It does not make sense to apply the SCALE and OFFSET to these pixels. Pixels with this value should be omitted from computations. The value that indicates "missing data" is chosen to be outside the expected range of actual data values. 

The PDS3 Data Dictionary defines MISSING_CONSTANT as follows: "The missing_constant element supplies the value used to indicate that no data were available." (https://pds.nasa.gov/datasearch/subscription-service/SS-20200212.shtml). Examples of its use are given in the PDS3 Standards Reference (https://pds.nasa.gov/datastandards/pds3/standards/sr/StdRef_20090227_v3.8.pdf).