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Re: Basic Issues using netcdf service & aggregation

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  • Subject: Re: Basic Issues using netcdf service & aggregation
  • Date: Wed, 12 Sep 2007 10:46:59 -0600
Hi Apurv:

1. you need to enable the NetCDF Subset Service in the config file, see:

 
http://www.unidata.ucar.edu/projects/THREDDS/tech/reference/ThreddsConfigXMLFile.html

2. In this element:

 <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
   <aggregation type="union"/>
 </netcdf>
You havent added any files, you cant use a datasetScan element here. You want something like 
<dataset name="Test all files in a directory" ID="testUnion" 
urlPath="satellite/union.nc"

   <metadata inherited="true">
     <serviceName>thisNETCDF</serviceName>
     <dataFormat>NetCDF</dataFormat>
   </metadata>

   <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
    <aggregation type="union">
      <scan location="/data/ldm/pub/native/satellite/3.9/WEST-CONUS_4km/" 
suffix=".nc" />
    </aggregation>
   </netcdf>

 </dataset>


see:

 http://www.unidata.ucar.edu/projects/THREDDS/tech/tutorial/NcML.htm

3. thanks for letting me know who you work for

4. in the future, send these questions to address@hidden


good luck!





Apurv Bhartia wrote:

Hi John,
I have basically started with THREDDS server and netCDF a couple of days back. I have had a look at the documentation provided but cannot figure this out. 
Two Issues -
1) I am trying to get the dataset use the netcdf service, but it fails giving me the error that 'service not found'. 

Below is the code -
<?xml version="1.0" encoding="UTF-8"?>
<catalog name="THREDDS Server Default Catalog : You must change this to fit your server!" xmlns=" http://www.unidata.ucar.edu/namespaces/thredds/InvCatalog/v1.0"; xmlns:xlink="http://www.w3.org/1999/xlink <http://www.w3.org/1999/xlink>"> 

  <service name="thisDODS" serviceType="OpenDAP" base="/thredds/dodsC/" />
<service name="thisNETCDF" serviceType="NetcdfServer" base="/thredds/ncServer/" /> 
  <datasetRoot path="test" location="content/testdata/"/>
<dataset name="Test Single Dataset" ID="testDataset" serviceName="thisNETCDF" 
           urlPath="test/testData.nc"/>
  <datasetScan name="Test all files in a directory" ID="testDatasetScan"
               path="testAll" location="content/testdata">
    <metadata inherited="true">
      <serviceName>thisNETCDF</serviceName>
    <dataFormat>NetCDF</dataFormat>
    </metadata>

    <filter>
      <include wildcard="*.nc"/>
    </filter>
    <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
    <aggregation type="union"/>
</netcdf>
  </datasetScan>
<catalogRef xlink:title="Test Enhanced Catalog" xlink:href="enhancedCatalog.xml" name=""/> 
</catalog>
2) Further, I have a few doubts regarding aggregation. I am trying to get the aggregation thing going. Basically, I'd like to take files from a specified directory and aggregate them (type = "union") 

<?xml version="1.0" encoding="UTF-8"?>
<catalog name="THREDDS Server Default Catalog : You must change this to fit your server!" xmlns=" http://www.unidata.ucar.edu/namespaces/thredds/InvCatalog/v1.0"; 
        xmlns:xlink="http://www.w3.org/1999/xlink";>

  <service name="thisDODS" serviceType="OpenDAP" base="/thredds/dodsC/" />
<service name="thisNETCDF" serviceType="NetcdfServer" base="/thredds/ncServer/" /> 
 <datasetRoot path="test" location="content/testdata/"/>
<dataset name="Aggregate all files in a directory" path="test"> <serviceName>thisDODS</serviceName> <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";> 
    <aggregation dimName = "refTime" type="joinExisting">
<scan location="content/testdata/" suffix=".nc"/> // this is the location,and aggregate all files ending with .nc 
    </aggregation>
    </netcdf>
  </dataset>
</catalog>
Objective is to take files from /content/testdata directory and aggregate them. It would be great if you can tell me where I am goofing up and how to go about it. 

Thanks a lot,
-Apurv