Re: [thredds] size limit for NcML values element entries?

• To: Steven Baum <baum@xxxxxxxxxxxxxxxx>
• Subject: Re: [thredds] size limit for NcML values element entries?
• From: "Signell, Richard" <rsignell@xxxxxxxx>
• Date: Fri, 8 Feb 2013 07:46:26 -0500

Steve,

I don't know the answer to your question about the size limit for
<values>, but there is another way to solve your problem..

You can write your lon,lat values to a netcdf file, and then use a
"union" aggregation that aggregates the "joinExisting"
aggregation with your grid file.

For example, if you have a bunch of files like:
mod_his_0001.nc
mod_his_0002.nc
...
and you create a netcdf file that contains the lon,lat variables:
lonlat.nc

you can aggregate them together like so:

<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
 <!-- union the (1) time aggregation with the (2) grid file -->
 <aggregation type="union">
  <!-- (1) time aggregate files like "mod_his_0001.nc" -->
  <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
   <aggregation dimName="time" type="joinExisting">
    <scan
     location="/home/baum/models/run01/"
     regExp=".*mod_his_[0-9]{4}\.nc$"/>
   </aggregation>
  </netcdf>
  <!-- (2) grid file -->
  <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";
   location="/home/baum/models/lonlat.nc"/>
 </aggregation>
</netcdf>

Make sense?

-Rich

P.S. Can you please ask the same question on stackoverflow.com and tag
with "netcdf" and "xml"?  I think as a community we should start to
get info like this captured in a place where others can comment and
improve the answers, and best answers can rise to the top.  It's a lot
easier than wading through mailing lists.  If you ask it, I promise to
answer.   And I need to get up to 1500 points so I can add an "ncml"
tag.   ;-)

On Thu, Feb 7, 2013 at 5:44 PM, Steven Baum <baum@xxxxxxxxxxxxxxxx> wrote:
>
> Is there a limit to the size or number of entries that can be placed within 
> the values
> NcML element?  I'm attempting to get a set of NetCDF files without lon/lat 
> variables -
> but with x/y variables - to be read as a featureCollection by adding NcML 
> entries of the
> form:
>
>       <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
>
>         <variable name="lat_rho" shape="eta_rho xi_rho" type="float">
>           <attribute name="units" type="String" value="degrees_north" />
>             <values>[671x191 blankspace-separated latitudes here]</values>
>         </variable>
>
> The lat and lon variables exist in a separate file and I've extracted them 
> into single
> strings using ncks which I've stuck between appropriate <values></values> 
> locations.
>
> The error messages in featureCollectionScan.log are:
>
> [2013-02-07T15:15:37.386-0600] ERROR ucar.nc2.ft.fmrc.Fmrc: makeFmrcInv
> java.lang.NullPointerException
>
> ....
>
> [2013-02-07T15:15:37.388-0600] ERROR ucar.nc2.ft.fmrc.Fmrc:
> /raid/data/txla_nesting6/.*\.nc$: makeFmrcInv failed
> java.lang.RuntimeException: java.lang.NullPointerException
>
> ....
>
> [2013-02-07T15:15:37.694-0600] WARN  ucar.nc2.ft.fmrc.GridDatasetInv: 
> GridDatasetInv
> using gds.getStartDate() for run date =%s
> [2013-02-07T15:15:37.694-0600] ERROR ucar.nc2.ft.fmrc.Fmrc: makeFmrcInv
> java.lang.NullPointerException
>
> ....
> [2013-02-07T15:15:37.695-0600] ERROR ucar.nc2.ft.fmrc.Fmrc:
> /raid/data/txla_nesting6/.*\.nc$: makeFmrcInv failed
> java.lang.RuntimeException: java.lang.NullPointerException
>
>
>
> _______________________________________________
> thredds mailing list
> thredds@xxxxxxxxxxxxxxxx
> For list information or to unsubscribe,  visit: 
> http://www.unidata.ucar.edu/mailing_lists/



-- 
Dr. Richard P. Signell   (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598

• Follow-Ups:
  • Re: [thredds] size limit for NcML values element entries?
    • From: Steven Baum

• References:
  • [thredds] size limit for NcML values element entries?
    • From: Steven Baum