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Re: [Fwd: Re: THREDDS and grib]

So the IOSP translate this as two separate Groups, one for each projection.
John, is there a way to aggregate on the dimension in one of the groups? I just tried 

<?xml version="1.0" encoding="UTF-8"?>
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
 <aggregation dimName="proj0.time" type="joinExisting">
   <netcdf location="file:Z:/kevinGribData/godas.P.19800105.grb" />
   <netcdf location="file:Z:/kevinGribData/godas.P.19800110.grb" />
   <netcdf location="file:Z:/kevinGribData/godas.P.19800115.grb" />
 </aggregation>
</netcdf>

but that didn't work. I got

java.lang.IllegalArgumentException: Dimension length =0 must be > 0
   at ucar.nc2.Dimension.setLength(Dimension.java:246)
   at ucar.nc2.Dimension.<init>(Dimension.java:192)
   at ucar.nc2.Dimension.<init>(Dimension.java:166)
at ucar.nc2.ncml4.AggregationExisting.buildDataset(AggregationExisting.java:70) 
   at ucar.nc2.ncml4.Aggregation.finish(Aggregation.java:249)
   at ucar.nc2.ncml4.NcMLReader.readNetcdf(NcMLReader.java:407)
   at ucar.nc2.ncml4.NcMLReader.readNcML(NcMLReader.java:360)
   at ucar.nc2.ncml4.NcMLReader.readNcML(NcMLReader.java:203)
   at ucar.nc2.ncml4.NcMLReader.readNcML(NcMLReader.java:153)
   at ucar.nc2.dataset.NetcdfDataset$1.open(NetcdfDataset.java:315)
   at ucar.nc2.NetcdfFileCache.acquire(NetcdfFileCache.java:205)
   at ucar.nc2.dataset.NetcdfDataset.acquireFile(NetcdfDataset.java:313)
   at ucar.nc2.ui.ToolsUI.openFile(ToolsUI.java:799)
   ...
Also, the OPeNDAP server shows duplicate variables in the DDS. What is the plan for serving datasets with Groups and such? Or is this fixed in 4.0? 

Ethan

Robb Kambic wrote:

On Wed, 5 Mar 2008, Ethan Davis wrote:


Hi guys,
Kevin at PMEL is trying to aggregate some GRIB files and running into problems. 

I have some sample files at /home/edavis/kevinGribData.
When I open them up in ToolsUI, I see a proj0 and proj1 structure. They each have a latLonCoordSys variable but I don't see a difference between them. 

Ethan,
there is a minor differance in the projections, ie p1.Lo1 != p2.Lo1. That's enough to cause problems in an aggregation. 

--------------------------------------------------------------------
GDSkey = 2494715761
La1 = -74.5

Lo1 = 0.5

La2 = 64.499
Lo2 = 359.5
--------------------------------------------------------------------
GDSkey = 2548847210
La1 = -74.0

Lo1 = 1.0

La2 = 64.999
Lo2 = 360.0
Before the aggreagtion could occur, some of the grid parameter would have to be reprojected to the other grid co-ordinates or the parameters would have to be seperated out into files according to co-ordinates and then aggregated. 


Robb...




I'm
guessing this is confusing the aggregation. Are there actually two different projections in each file or is the GRIB library or IOSP mapping things poorly? 

Could you take a look at these files and let me know what is up?

Thanks,

Ethan

--
Ethan R. Davis                                Telephone: (303) 497-8155
Software Engineer                             Fax:       (303) 497-8690
UCAR Unidata Program Center                   E-mail:    address@hidden
P.O. Box 3000
Boulder, CO 80307-3000 http://www.unidata.ucar.edu/ ---------------------------------------------------------------------------
=============================================================================== 
Robb Kambic                       Unidata Program Center
Software Engineer III               Univ. Corp for Atmospheric Research
address@hidden           WWW: http://www.unidata.ucar.edu/
=============================================================================== 

--
Ethan R. Davis                                Telephone: (303) 497-8155
Software Engineer                             Fax:       (303) 497-8690
UCAR Unidata Program Center                   E-mail:    address@hidden
P.O. Box 3000
Boulder, CO  80307-3000                       http://www.unidata.ucar.edu/
---------------------------------------------------------------------------