"(i.e. sections) of contiguous pixels that can be obtained from an NDF, subject to the constraint that no chunk should contain more than a specified maximum number of pixels. More specifically, given the maximum number of pixels in a chunk (MXPIX), this routine returns the maximum value which can be supplied for the ICHUNK argument of the routine NDF_CHUNK if a valid NDF identifier for a chunk of contiguous pixels is to be returned.
This routine is provided to calculate an upper bound on the number of chunks for DO-loops which process NDFs by dividing them into separate chunks by means of calls to the routine NDF_CHUNK.
A value of zero will be returned for the NCHUNK argument if this routine is called with STATUS set. The same value will also be returned if the routine should fail for any reason.