[jira] [Commented] (SIS-533) Add "Rotated Latitude/Longitude" coordinate operation

["Martin Desruisseaux (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SIS-533?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17484412#comment-17484412 ] 

Martin Desruisseaux commented on SIS-533:
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h1. Comparison with UCAR netCDF library
The south pole case is consistent with {{ucar.unidata.geoloc.projection.RotatedLatLon}} in UCAR netCDF library. But for the north pole case, {{ucar.unidata.geoloc.projection.RotatedPole}} in UCAR netCDF library version 5.5.2 gives results with an offset of 180° in longitude values compared to our implementation. But geometrical reasoning suggests that our implementation is correct: if we rotate the pole to 60°N, then latitude of 54°N on Greenwich meridian become only 6° below new pole, i.e. 84°N but still on the same meridian (Greenwich) because we did not cross the pole.


> Add "Rotated Latitude/Longitude" coordinate operation
> -----------------------------------------------------
>
>                 Key: SIS-533
>                 URL: https://issues.apache.org/jira/browse/SIS-533
>             Project: Spatial Information Systems
>          Issue Type: New Feature
>          Components: Referencing
>            Reporter: Martin Desruisseaux
>            Assignee: Martin Desruisseaux
>            Priority: Major
>             Fix For: 1.2
>
>
> Add the "Rotated Latitude/Longitude" coordinate operation as described by the World Meteorological Organization (WMO) in GRIB2 template 3.1. This coordinate operation has no EPSG code (at the time of writing this issue).
> In the UCAR netCDF library,  this is named {{"rotated_latlon_grib"}} with the following parameters:
> * {{"grid_south_pole_latitude"}}
> * {{"grid_south_pole_longitude"}}
> * {{"grid_south_pole_angle"}}
> Note that UCAR also defines a north pole variant named {{"rotated_latitude_longitude"}} with the following parameters:
> * {{"grid_north_pole_latitude"}}
> * {{"grid_north_pole_longitude"}}
> * {{"north_pole_grid_longitude"}}
> I didn't found WMO names for parameters. In absence if alternatives, Apache SIS currently uses the netCDF parameter names. Those names seem to be used by the PROJ library as well.



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