Reading .pp files

1

I am working with a computer science student who is playing with visualisation tools for UM data that is presently in .pp files. Their preference is to work in either C# or C++, are you aware of any utilities for reading .pp in these languages, or are we better off converting these to another format?

2

Hi Todd

CMS have spent years developing and continue to develop cf-python and cf-plot – python based utilities. Could your student benefit from those?

Grenville

3

My personal preference is to convert to netCDF as there is a much larger array of tools available for the format.

I use a basic utility using cf-python which is installed in its own conda env:

cfpython_pe_to_nc.py

import sys
import cf

def main():
    if len(sys.argv) != 2:
        print('Usage: python cfpython_pe_to_nc.py <pe_file>')
        sys.exit(1)

    ds = cf.read(sys.argv[1])
    cf.write(ds, sys.argv[1]+'.nc')
    print('Successfully wrote nc file: {0}'.format(sys.argv[1]+'.nc'))

if __name__ == "__main__":
    main()

pe_to_nc.sh

#!/bin/bash

if [ "$#" -ne 1 ]; then
    echo "Incorrect usage, only input should be input pe_file"
    exit 1
fi

if [ -f "/home/rw796/miniconda3/etc/profile.d/conda.sh" ]; then
  . "/home/rw796/miniconda3/etc/profile.d/conda.sh"
else
  export PATH="/home/rw796/miniconda3/bin:$PATH"
fi

# ARGUMENTS
PE_FILE=$1

if [ ! -f "$PE_FILE" ]; then
    echo "could not find provided pe_file"
    exit 1
fi

if ! conda activate cfpython; then
    echo "unable to activate cfpython env"
    exit 1
fi

python /home/rw796/rw_utils/cfpython_pe_to_nc.py "$PE_FILE"


conda deactivate
4

Thanks, Rob and Grenville. I’m aware of the cf tools and have encouraged their use. The student reported vague installation troubles that I have not been able to assist with for lack of information, and I wanted to check whether anything closer to their comfort zone happened to exist.

5

Hi toddj, to add to the thread, if you can encourage them to let us know more about the installation issues with cf-python or related libraries, here or otherwise, we can help them get set up. As for your original question:

I wanted to check whether anything closer to their comfort zone happened to exist.

I am not aware about any C# or C++ to directly read and work with PP, so…

or are we better off converting these to another format?

…yes, I think if they want to work with the original PP and those languages they would need to convert, e.g. your student could convert from PP to netCDF, e.g. with cf-python, as per Rob Waters example snippets or otherwise, and then use netCDF-C++ (GitHub - Unidata/netcdf-cxx4: Official GitHub repository for netCDF-C++ libraries and utilities.).

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