CF-NETCDF.NC: Difference between revisions
From BAWiki
imported>Lang Guenther (→Purpose of these BAWiki Pages: link to cf metadata convention changed) |
imported>Lang Guenther (informations about file chunking added) |
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|filetype=cf-netcdf.nc | |filetype=cf-netcdf.nc | ||
|version=May 2012 | |version=May 2012 | ||
|version_descr= | |version_descr=August 2014 | ||
|significance= | |significance= | ||
* BAW instance of a [[NETCDF.CDF|NetCDF]] file. | * BAW instance of a [[NETCDF.CDF|NetCDF]] file. | ||
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## '''coordinate-variable''' data, | ## '''coordinate-variable''' data, | ||
## data for ordinary''' variables''', for which only one data record is stored in the file, and finally | ## data for ordinary''' variables''', for which only one data record is stored in the file, and finally | ||
## data for '''record-variables''' (which have one unlimited dimension, e.g.''' time'''), which can be stored several times. | ## data for '''record-variables''' (which have one unlimited dimension, e.g.''' time'''), which can be stored several times. | ||
READ performance for large CF-NetCDF data files may strongly depend on the inner structure of the data file. The size of a data block (or chunk) which is accessed by one READ is significant in this context. A file can be considered as ''well structured'' if time series access as well as spatial access can be executed with similar effort (number of READs required). This can be achieved using appropriate chunk sizes for the variables stored. More informations can be found here: | |||
# [http://www.unidata.ucar.edu/blogs/developer/en/entry/chunking_data_why_it_matters ''Chunking Data: Why it Matters''], and | |||
# [http://www.unidata.ucar.edu/blogs/developer/en/entry/chunking_data_choosing_shapes ''Chunking Data: Choosing Shapes'']]. | |||
|nutzerprogramme=[[ArcGIS: Import data from CF-NetCDF file|ArcGIS]], [[DATACONVERT]], [[GRIDCONVERT]], [[NCAGGREGATE]], [[NCANALYSE]], [[NCPLOT]], [[QUICKPLOT]], [[UNTRIM2]], [[UNTRIM2007]] | |nutzerprogramme=[[ArcGIS: Import data from CF-NetCDF file|ArcGIS]], [[DATACONVERT]], [[GRIDCONVERT]], [[NCAGGREGATE]], [[NCANALYSE]], [[NCPLOT]], [[QUICKPLOT]], [[UNTRIM2]], [[UNTRIM2007]] | ||
|language=Fortran90 | |language=Fortran90 | ||
Revision as of 08:09, 13 August 2014
Basic Information
File-Type
cf-netcdf.nc
File-Form
UNFORMATTED
Version
May 2012
Description-Date
August 2014
Significance of the File
- BAW instance of a NetCDF file.
- NetCDF conventions, used to store BAW specific data, are documented in detail in the NetCDF-Pages of BAW-Wiki.
- CF compliance verified using the NCAS CF Compliance Checker.
- Since May 2011 NetCDF-4/HDF5 is supported (see Unidata, NetCDF).
File-Contents (in Catchwords)
- header with metadata:
- list of dimensions (name and length),
- list of variables (name, type and dimension(s)) for which data are stored in the file,
- attributes related to variables (long_name, units etc.), and
- global attributes (title, history etc.).
- Remark: the names of attributes as well as standard variable names should be chosen according to the following given conventions:
- data for all variables stored in the file:
- coordinate-variable data,
- data for ordinary variables, for which only one data record is stored in the file, and finally
- data for record-variables (which have one unlimited dimension, e.g. time), which can be stored several times.
READ performance for large CF-NetCDF data files may strongly depend on the inner structure of the data file. The size of a data block (or chunk) which is accessed by one READ is significant in this context. A file can be considered as well structured if time series access as well as spatial access can be executed with similar effort (number of READs required). This can be achieved using appropriate chunk sizes for the variables stored. More informations can be found here:
Programs using this Type of File
ArcGIS, DATACONVERT, GRIDCONVERT, NCAGGREGATE, NCANALYSE, NCPLOT, QUICKPLOT, UNTRIM2, UNTRIM2007
Example-File
$PROGHOME/examples/lib/l_grid/lg.all_CF-NetCDF_Info.nc
$PROGHOME/examples/lib/h_grid/g05-Content.CF-NetCDF.nc
$PROGHOME/examples/lib/h_grid/UNTRIM-Content.CF-NetCDF.nc
$PROGHOME/examples/lib/h_grid/UTRSUB-Content.CF-NetCDF.nc
$PROGHOME/examples/lib/p_grid/profil05-Content.CF-NetCDF.nc
$PROGHOME/examples/lib/io_insel/insel.netcdf-cf.nc
back to: File Descriptions