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Re: [netcdf-java] cordex rotatedpole help

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