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 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
I don't know the answer to your question about the size limit for the <values> tag, 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 to create a dataset that virtually joins that netcdf file to another netcdf file (or aggregation of netcdf files)
For example, if you have a bunch of files like:
mod_his_0001.nc
mod_his_0002.nc
...
that you want to aggregate along the time dimension 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>