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[IDV #GYA-404192]: aggregatin nc files

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  • Subject: [IDV #GYA-404192]: aggregatin nc files
  • Date: Tue, 05 Aug 2008 10:05:19 -0600
Hi HP-

> Full Name: HansPeter Roesli
> Email Address: address@hidden
> Organization: EUMETSAT
> Package Version: 2.6a3 build date:@DATE@
> Operating System: Linux
> Hardware: Java: home: /home/user/IDV_2.6a3/jre version: 1.6.0_07 j3d:1.5.2 
> fcs (build4)
> Description of problem: HI
> 
> I tried to aggregate a sequence of daily nc files showing global NO2 columns 
> from GOME-2 on
> Metop 
> (http://wdc.dlr.de/data_products/SERVICES/GOME2NRT/archive.php?spec=NO2).
> However, it does not work and ends this state. I also attach a sample file. 

These files have no time in them.  Were you trying to use the 
"Make a time sequence from single time grids/images" formula to aggregate these?
You could create an NcML file to do the aggregation manually.  You can 
see some examples at:

http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Aggregation.html

under the JoinNew section.  You would create a new time dimension like:

<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>

   <variable name="time">
     <attribute name="units" value="days since 2008-07-22 00:00"/>
     <attribute name="_CoordinateAxisType" value="Time" />
     <values>0 1 2</values>
   </variable>

   <aggregation dimName="time" type="joinNew">
    <variableAgg name="N02"/>
    <netcdf 
location="file:/home/user/Desktop/20080720-31_ma_GOME2_NO2Column/GOME2.L3.NO2.VCD.NRT.GDP-4.20080722.nc"
 />
    <netcdf 
location="file:/home/user/Desktop/20080720-31_ma_GOME2_NO2Column/GOME2.L3.NO2.VCD.NRT.GDP-4.20080723.nc"
 />
    <netcdf 
location="file:/home/user/Desktop/20080720-31_ma_GOME2_NO2Column/GOME2.L3.NO2.VCD.NRT.GDP-4.20080724.nc"
 />
   </aggregation>

</netcdf>

> BTW marcos
> field short and
> long name both deliver the same string (NO2). That's porbably due to the 
> coding by the provider, isn't it?

For netCDF files, we use the "long_name" attribute to get a descriptive name.
However, these files look like:

   float NO2(latitude=720, longitude=1440);
     :NO2 = "NO2_Total_Column";
     :units = "[10^15_molec_cm-2]";
     :value = "Retrieval for given date";
     :date = "20080722";
     :version = "GDP-4.2";

if the :N02 attribute was  :long_name, then we'd pick it up.

Also, none of the units are valid specifications.

Don

> Creating display: Color-Shaded Plan View
> org.python.core.PyException
> 
> ******************
> Stack trace:
> Traceback (innermost last):
> File "<string>", line 1, in ?
> File "<string>", line 230, in makeTimeSequence
> at visad.Set.<init>(Set.java:148)
> at visad.SimpleSet.<init>(SimpleSet.java:58)
> at visad.SampledSet.<init>(SampledSet.java:47)
> at visad.GriddedSet.<init>(GriddedSet.java:72)
> at visad.Gridded1DSet.<init>(Gridded1DSet.java:130)
> at visad.Gridded1DDoubleSet.<init>(Gridded1DDoubleSet.java:107)
> at visad.Gridded1DDoubleSet.create(Gridded1DDoubleSet.java:174)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at 
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at 
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> 
> visad.UnitException: visad.UnitException: Set: units dimension 1 does not 
> match Domain dimension 2
> 
> 
> 


Ticket Details
===================
Ticket ID: GYA-404192
Department: Support IDV
Priority: Normal
Status: Open