ncagg: Aggregate NetCDF files

So… You want to aggregate NetCDF files? Ncagg is software that enables you to combine multiple input NetCDF files into a single output NetCDF file.

  • For interactive use: The CLI.
  • For programatic use: ncagg.aggregator.aggregate().

Advanced users may want to familiarize themselves with Templates.

ncagg features

  • aggregate files along unlimited dimensions
  • insert fill values in gaps
  • deduplicate records
  • sort a dimension by an indexing variable
  • resolve global attributes according to a variety of strategies
  • subset variables and dimensions
  • create new dimensions variables in each input file variables with no existing unlimited dimension

This software was developed for the situation we faced with GOES-R series satellite data. We receive data in small “granules”, where each granule is a NetCDF file containing several seconds or minutes of data. This format is very cumbersome for analysis, requiring thousands of file system operations just to read a single day of data. Using ncagg we can combine these small NetCDF files into a single dayfile for easier use. Often, we also create larger aggregations, a single file containing the entire year, or even mission.

Or, perhaps you have daily model result files over a month, and analysis is going to be easier if you could just operate on a single file.

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