Update Ultra maps to rectangular projection (for all but intensity) - Card 3158

[jtniehof]

Summary

See IMAP-Science-Operations-Center/imap_processing#3012 for corresponding L2 issue.

All quantities other than intensity in Ultra maps should be created directly via rectangular projection. The L2 code is being updated, which means the L3 code that calls it probably also should be.

Requirements

• Intensity in SP-corrected maps should be created the same way as currently
  • Regenerate HEALPix intensity map and HEALPix survival probability map
  • Divide, and interpolate to rectangular
• All other quantities in the SP maps should via direct rectangular map (hopefully this comes from just using the L2 code)
• Combined non-SP maps also probably largely the same, just directly process the non-intensity quantities in rectangular
• Should be no impact on spectral index map, as they are made directly from the rectangular intensity map

Related tickets

IMAP-Science-Operations-Center/imap_processing#3012

[pleasant-menlo]

@jtniehof Picking this up today - are we going to continue to calculate the intensity uncertainties in healpix?

~ Logan

[jtniehof]

Discussed on the call yesterday, but IIRC we figured uncertainties are probably also in healpix, check the L2 code.

[pleasant-menlo]

@jtniehof - solid_angle and exposure_factor are both used in the calculations for ena_intensity and ena_intensity_stat_uncert in the L2 ultra code. Because we are going to continue processing intensities from the healpix L2 map, should we also continue processing/propagating solid_angle, exposure_factor, and potentially obs_date / obs_date_range from the healpix map? In theory they shouldn't be different, but if they are - should we be checking to make sure things like these are consistent across the rectangular and healpix maps during processing?

~ Logan

[jtniehof]

Those should all just propagate through from the rectangular map. They will likely be slightly inconsistent with values from the HEALPix->rectangular interpolation, so don't do a consistency check.

This is the thing that concerns me about this whole change, so I agree it feels weird.