Hi Valentijn,
> thanks for your work. can you send us an example of how ncml aggreagtion
> over time could work for the OpenDAP server that worked:
>http://www.cooa.unh.edu/opendap/nph-dods/webcoast/dods_data/COOA_Satellite_Data_Products/
I took a look at this dataset. Not being very familiar with this dataset, I
didn't dig too much into which datasets would make sense to aggregate together.
However, I did run into a problem even accessing the data from within the
netCDF-java library. I think it has to do with how the various layers deal with
variable names. In the case I was looking at one of the variable containers was
called "Data Fields. The problem is that the netCDF layer doesn't like spaces
in variable names so it encodes it as an underscore ("_"). When I tried to ask
for the data the netCDF-java layer did not succeed. I think it has to do with
this variable name encoding. I'm double checking with John Caron (who is out of
town for a few days) on this.
However, I looked at the Pathfinder data from earlier in this ticket and got an
aggregation working. Here is the catalog I put together:
<?xml version="1.0" encoding="UTF-8"?>
<catalog xmlns="http://www.unidata.ucar.edu/namespaces/thredds/InvCatalog/v1.0";
xmlns:xlink="http://www.w3.org/1999/xlink";
version="1.0.1" >
<service name="thisDODS" serviceType="OPENDAP" base="/thredds/dodsC/" />
<dataset name="valentijn's agg of UNH data" ID="valentijn"
urlPath="valentijnAggOfUNH">
<metadata>
<serviceName>thisDODS</serviceName>
<dataType>Grid</dataType>
</metadata>
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<variable name="time">
<attribute name="_CoordinateAxisType" type="String" value="Time" />
</variable>
<variable name="lat">
<attribute name="_CoordinateAxisType" type="String" value="Lat" />
</variable>
<variable name="lon">
<attribute name="_CoordinateAxisType" type="String" value="Lon" />
</variable>
<variable name="dsp_band_1">
<attribute name="_CoordinateAxes" type="String" value="time lat lon" />
</variable>
<aggregation dimName="time" type="joinNew">
<variableAgg name="dsp_band_1" />
<netcdf
location="http://dods.gso.uri.edu/dods-3.4/nph-dods/Pathfinder/Northwest_Atlantic/6km/declouded/1999/1/f99001082417.hdf";
coordValue="1999-01-01T08:24:17Z" />
<netcdf
location="http://dods.gso.uri.edu/dods-3.4/nph-dods/Pathfinder/Northwest_Atlantic/6km/declouded/1999/1/f99001181038.hdf";
coordValue="1999-01-01T18:10:38Z" />
<netcdf
location="http://dods.gso.uri.edu/dods-3.4/nph-dods/Pathfinder/Northwest_Atlantic/6km/declouded/1999/1/f99001195049.hdf";
coordValue="1999-01-01T19:50:49Z" />
<netcdf
location="http://dods.gso.uri.edu/dods-3.4/nph-dods/Pathfinder/Northwest_Atlantic/6km/declouded/1999/1/f99002081244.hdf";
coordValue="1999-01-02T08:12:44Z" />
<netcdf
location="http://dods.gso.uri.edu/dods-3.4/nph-dods/Pathfinder/Northwest_Atlantic/6km/declouded/1999/1/f99002180018.hdf";
coordValue="1999-01-02T18:00:18Z" />
</aggregation>
</netcdf>
</dataset>
</catalog>
The various "_Coordinate*" attributes make the dataset recognizable as a Grid
dataset to the ToolsUI.
Hope this helps.
Let me know if you have any more questions.
Ethan
Ticket Details
==================
Ticket ID: ETD-820941
Department: Support THREDDS
Priority: Critical
Status: Open
