  This directory provides a sample NcML file so that users can fix some issues 
 that the H4CF Conversion Toolkit cannot handle.

  Although the H4CF Conversion Toolkit satisfies the key requirements of the 
CF-conventions that make NetCDF visualization tools work, there are many non-CF
 compliant attributes that the toolkit doesn't process. To standardize such 
attributes that the toolkit does not handle, we recommend users to utilize NcML
 solution.

  For example, the h4tonccf converter can convert AIRS Level 3 file into 
 an NetCDF file. If you examine the converted file carefully, you'll see 
that the converted file has many variables that do not have units attribute 
because they are not provided in the original file. You can add or overwrite
 units attribute and its value by writing a simple NcML file. Then, you can 
open the NcML file directly with NetCDF-Java visualization tools like IDV [1] 
and Panoply [2]. Magically, the correct unit information will be displayed in
 the final plot.

 You can also create a new NetCDF file from NcML using the ToolsUI [3] 
application available from Unidata. By creating the attribute-corrected NetCDF
 file from the converted file using the ToolsUI, NetCDF-C visualization tool
 like GrADS [4] can also visualize the new NetCDF file*. For more information 
about this technique, please read the section "Writing out files modified with
 NcML" from the ToolsUI tutorial [5].

 If you want to edit a batch of converted NetCDF files via command line tool
 instead of ToolsUI GUI tool, you can download netcdfAll-4.3.jar [3] and issue
 a command like below [6]:

 %java -Xmx1g -classpath ./netcdfAll-4.3.jar ucar.nc2.dataset.NetcdfDataset -in a.ncml -out b.nc

 We assume that you put the downloaded netcdfAll-4.3.jar file in the same directory
 where a.ncml file exists. The a.ncml should contain a line that refers to the 
 converted file a.nc in the same directory.

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

 
 *This may not always work because GrADS do not necessarily follow the same 
 conventions that NetCDF-Java tools use.

References
[1] https://www.unidata.ucar.edu/software/idv/
[2] http://www.giss.nasa.gov/tools/panoply/
[3] http://www.unidata.ucar.edu/downloads/netcdf/netcdf-java-4/index.jsp
[4] http://www.iges.org/grads/
[5] http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Tutorial.html 
[6] http://www.unidata.ucar.edu/software/netcdf-java/reference/manPages.html 


