# Changes between Version 9 and Version 10 of EcomsUdg/RPackage/Functions

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Timestamp:
May 17, 2013 11:17:01 AM (8 years ago)
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 v9 '''__1. ncmlAggreg.R__''' == makeNcmlDataset == A NcML file is a [http://en.wikipedia.org/wiki/XML XML representation] of netCDF metadata. This is approximately the same information one gets when dumping the header of a netCDF file (e.g. by typing on the terminal the command ncdump -h). By means of NcML it is possible to create virtual datasets by modifying and [http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Aggregation.html aggregating] other datasets, thus providing maximum flexibility and ease of access to data stored in collections of files containing data from different variables/time slices, as far as all data are queried from a single NcML representation of the dataset. The function is intended to deal with reanalysis, forecasts and other climate data products, often consisting of collections of netCDF files corresponding to different variables and partitioned by years/decades or other time slices. ''__Description__'' NcML files are the basis on which the different R functions here described are based on. Generates a NcML file from a collection of netCDF files. The ncmlAggreg.R function generates a NcML file from a collection of netCDF or GRIB files stored in a common directory. The function is called as follows: ''__Usage__'' {{{ > ncmlAggreg(source.dir, output.dir = getwd(), file.name) makeNcmlDataset(source.dir, ncml.file) }}} The arguments are next described: ''__Details__'' A NcML file is a [http://en.wikipedia.org/wiki/XML XML] representation of netCDF metadata. This is approximately the same information one gets when dumping the header of a netCDF file (e.g. by typing on the terminal the command ncdump -h). By means of NcML it is possible to create virtual datasets by modifying and  aggregating other datasets, thus providing maximum flexibility and ease of access to data stored in collections of files containing data from different variables/time slices. The function makeNcmlDataset is intended to deal with reanalysis, forecasts and other climate data products, often consisting of collections of netCDF files corresponding to different variables and partitioned by years/decades or other time slices. It operates by applying to types of [http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Aggregation.html aggregation operations]: 1. Union 2. JoinExisting * source.dir: character string indicating a valid path of the directory containing the files