Holes in heterodyne maps

HARP has only twelve operational receptors since May 20.  If one or two also suffer from interference and fail quality assurance, then there can be locations in the reduced spectral cubes where no valid data are present.  Such missing spectra (shown in blue) will often be arranged in a grid pattern as in the example below.

This can create issues if you wish to integrate flux or simply improve the cosmetic appearance.

One approach is to smooth the data but this degrades all the spectra.  Instead use KAPPA::FILLBAD. This replaces just the bad values with a smooth function derived from neighbouring values, derived by iterating to a solution of Laplace's equation.

Just using FILLBAD's default values will duly fill in the holes.  You might prefer not to smooth in the spectral axis by setting Parameter SIZE to [s,s,0] where s is the initial scale length in pixels.  The zero means do not smooth along the third axis. The scale length should have a value about half the size of the largest region of bad data to be replaced.  Since the largest bad regions apart from the cube peripheries are two pixels across, a command like this

fillbad in=holey out=filled  size="[1,1,0]"

is appropriate.  The graphic below shows the same region as before, but with the holes filled in.

FILLBAD does what it says on the tin.

There will be some smoothing, but it's not obvious.  Below is a KAPPA::CLINPLOT graphic for a part of the filled cube.  Each spectrum is a pixel in the image above. Can you identify the three spectra which were previously bad?