sampleprojectionoffset negated and 1 pixel shifted

[thareUSGS]

ISIS_contrib/isis2pds_label_translator/isis3_lbl_to_pds3_lbl.py

Line 251 in 979ccac

sampleprojectionoffset = PUnits((-0.5 + (-1 * ULX.value / mapscale_x)), 'PIXELS')

I am pretty sure this output sampleprojectionoffset is being computed incorrectly here, but It would be good to get another set of eyes on it. The fix appears to be simply removing the negation as shown in the code below (which also helps with the 0.5 shift to be subtracted in the correct direction).

    sampleprojectionoffset = PUnits((-0.5 + (ULX.value / mapscale_x)), 'PIXELS')
elif isinstance(ULX, (int, float)):
    sampleprojectionoffset = PUnits((-0.5 + (ULX / mapscale_x)), 'PIXELS')

UPDATE - ignore this change

[thareUSGS]

Ahh - I think I found the issue. There should be no need to negate the mapscale_x . That is not impacted by East/West longitude system. Since this was only impacting images which were West, we didn't run into the problem.

ISIS_contrib/isis2pds_label_translator/isis3_lbl_to_pds3_lbl.py

Line 208 in 979ccac

if positivelongdir == "EAST":

For testing check out. Callisto_Voyager_GalileoSSI_global_mosaic_1km.lbl
https://astrogeology.usgs.gov/search/map/Callisto/Voyager-Galileo/Callisto_Voyager_GalileoSSI_global_mosaic_1km

So the leave the code above alone and I think update below (but still need help to test).

mapscale_x = mapscale
mapscale_y = (-1 * mapscale)

if positivelongdir == "EAST":
    easternmostlong = isis3lbl['IsisCube']['Mapping']['MaximumLongitude']
    westernmostlong = isis3lbl['IsisCube']['Mapping']['MinimumLongitude']
elif positivelongdir == "WEST":
    easternmostlong = isis3lbl['IsisCube']['Mapping']['MinimumLongitude']
    westernmostlong = isis3lbl['IsisCube']['Mapping']['MaximumLongitude']