Dear Egil,
My guess would be that the problem lies in the underlying Java-NetCDF libraries
- hopefully one of the relevant folk can reply to confirm or deny! I wonder if
this is fixed in a more recent version of THREDDS?
Best wishes,
Jon
----------------------------------------------------------------------
Message: 1
Date: Fri, 25 Jan 2013 16:28:32 +0100
From: Egil St?ren <egil.storen@xxxxxx>
To: thredds@xxxxxxxxxxxxxxxx
Cc: ?ystein God?y <o.godoy@xxxxxx>, Steinar Eastwood
<steinar.eastwood@xxxxxx>, Arild Burud <arild.burud@xxxxxx>
Subject: [thredds] Curious effect from attributes
semi_major/minor_axis on southern hemisphere images created by ncWMS
Message-ID: <5102A4A0.5060002@xxxxxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Dear all,
We have a netCDF file containing ice concentrations around antarctica that is
available at
http://thredds.met.no/thredds/catalog/egiltest/ES/data/catalog.html?dataset=egiltest/ES/data/iceconc.nc.
Using the Godiva2 viewer, it is obvious that the data is displayed inverted
along a vertical line centred on the map. This is most easily seen using the
south polar stereographic projection.
The netCDF file has a variable containing projection info:
int Polar_Stereographic_Grid ;
Polar_Stereographic_Grid:grid_mapping_name =
"polar_stereographic" ;
Polar_Stereographic_Grid:straight_vertical_longitude_from_pole
= 0.f ;
Polar_Stereographic_Grid:latitude_of_projection_origin = -90.f ;
Polar_Stereographic_Grid:standard_parallel = -70.f ;
Polar_Stereographic_Grid:false_easting = 0.f ;
Polar_Stereographic_Grid:false_northing = 0.f ;
Polar_Stereographic_Grid:semi_major_axis = 6378273.f ;
Polar_Stereographic_Grid:semi_minor_axis = 6356890.f ;
Polar_Stereographic_Grid:proj4_string = "+proj=stere +a=6378273
+b=6356889.44891 +lat_0=-90 +lat_ts=-70 +lon_0=0" ;
When I removed the following attributes from this variable, the data suddenly
displayed correctly in Godiva2:
Polar_Stereographic_Grid:semi_major_axis = 6378273.f ;
Polar_Stereographic_Grid:semi_minor_axis = 6356890.f ;
The modified version can be seen at
http://thredds.met.no/thredds/catalog/egiltest/ES/data/catalog.html?dataset=egiltest/ES/data/iceconc_1.nc.
Since these attributes only gives a more exact description of the shape of the
earth (compared to not having them), I think there must be a bug somewhere.
Have anybody experienced this behaviour? Is this a known bug?
We are using thredds version 4.2.9.
Best regards,
Egil St?ren
Norwegian Meteorological Institute
End of thredds Digest, Vol 48, Issue 14
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