Le 30/06/2022 à 18:53, John Caron a écrit :
BTW, grid_north_pole_longitude = 180.0 may be a mathematically
degenerate case, giving spurious results. something to look at closer.
perhaps Martin knows?
In the particular case where grid_north_pole_latitude is 90°, indeed I
think it degenerate (I would need to test for making sure). Which leads
me to the second issue:
<variable name="rotated_pole" shape="" type="char">
<attribute name="grid_mapping_name"
value="rotated_latitude_longitude" />
<attribute name="grid_north_pole_longitude" type="float" value="0.0" />
<attribute name="grid_north_pole_latitude" type="float" value="90.0" />
</variable>
It looks like an identity transform to me. Above parameters said that we
relocate the pole at 90°N 0°E, which means that we do not move the pole
at all. Looking at the equations, they indeed seem to simplify to
"output = input". Again I would need to test for making sure (just did
the math in my head, I almost always do mistakes in those cases).
Martin
