I'm not using FileWriter, I'm using NetcdfFileWriteable, which creates
NetCDF-3. I figured I needed the "Conventions:CF-1.6" attribute, and that the
names of the dimensions in the documentation is ambiguous (should I use
profiles/stations or profile/station)?
One note, both of these classes are deprecated, and I should apparently use
FileWriter2(?). However then I have to work with already created NetCDF files,
and I would like to be able to create one programmatically from scratch. But
this is perhaps something that is not going to be supported by NetCDF-java in
future versions since those classes are deprecated, and I should really create
the basic structures in some files so that the software has something to start
with?
Aleksander
Roland Schweitzer - NOAA Affiliate <roland.schweitzer@xxxxxxxx> , 1/24/2014
11:47 PM:
What netCDF version do you use in you FileWriter.createNew?
I'm able to make CF files for point features readable by toolsUI, but I
restrict myself to NetcdfFileWriter.Version.netcdf3?
Roland
On Fri, Jan 24, 2014 at 7:55 AM, Aleksander Vines <aleksander.vines@xxxxxxxx>
wrote:
Hi,
I need some help with the creation of a NetCDF file.
I'm attempting to create the NetCDF file programmatically. I have a lot of
point data, and I want to be able to create different types of NetCDF-files
after extracting different subsets of these points. I want the files to conform
to CF-1.6 (as far as its possible with the input I got).
I'm using NetCDF-java 4.3.
I've found a "Short guide to writing files using CF-1.6 Discrete Sampling
Features Conventions":
http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/reference/FeatureDatasets/CFpointImplement.html
From this guide, I concluded that I should support the format specified in
CF-1.6 H5.3 (see below) in my application (I'm also writing other kind of
formats)
http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#idp8432528
I've figured one obvious error in this example, and that is that they
referred to name_strlen as a dimension without specifying it in the dimension
list.ncdump of the file I've created: http://pastebin.com/fsPGX5LD I've
changed station_info to a 2D char array (as far as I understand, this is just
some extra info and it shouldn't make a difference that I changed it to be a
char/String(2D)?) I miss a few long_names, and a few standard names are not
the "correct" standard names, but I can't figure out why this is not working.
All seems nice so far, but when I try to read this netCDF-file with ToolsUI
4.3, I get this error message: http://i.stack.imgur.com/kmAqR.png Can't open
x.ncNestedTable: cant find variable time for coordinate type TimeNestedTable:
cant find variable lat for coordinate type Lat NestedTable: cant find variable
lon for coordinate type LonTable Structure(record) featureType POINT:
lat/lon/time coord not foundFailed to find FeatureDatasetFactory for=x.nc
datatype=ANY_POINT Could the problem have something to do with the following
comment in the "Short guide to writing files using CF-1.6 Discrete Sampling
Features Conventions", under 9.5: "CDM: A variable representing the instance id
is required, indicated by an attribute named cf_role, which follows all the CF
rules above."
It is absolutely not a requirement that the file is read by ToolsUI 4.3, but
the fact that it can't be read from there probably indicates that something is
wrong with the format (ncWMS can't read the file either).
I'm not sure if it makes any difference to show the code here, but here is the
method that writes to the netCDF file: http://pastebin.com/QTHKUyw8 ;(and yes, I
know NetcdfFileWriteable is deprecated, but in my opinion, your documentation
is quite difficult to use, and the "latest" examples (
https://www.unidata.ucar.edu/software/thredds/current/netcdf-java/tutorial/ ;
http://www.unidata.ucar.edu/software/netcdf/examples/programs/ ;) seems to be
using this class)
Any help with this problem would be greatly appreciated :)
Many Thanks,Aleksander Vines
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