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.