FM15_transform

FM15_transform provides functionality to transform raw FM15 (METAR) TAC messages into their corresponding bufr4 translations as well as extraction of geojson records of the individual observations formatted for use by a WIS2 node.

Installation

Requirements

• Python 3.7 and above
• ecCodes
• UDUNITS-2

Dependencies

Dependencies are listed in requirements.txt. Dependencies are automatically installed during FM15_transform installation.

pip

Install latest stable version from PyPI.

pip3 install FM15_transform

UDUNITS-2 Installation and Configuration

UDUNITS-2 is a C library that provides support for units of physical quantities

If the UDUNITS-2 shared library file (libudunits2.so.0 on GNU/Linux or libudunits2.0.dylibfile on MacOS) is in a non-standard location then its directory path should be added to the LD_LIBRARY_PATH environment variable. It may also be necessary to specify the location (directory path and file name) of the udunits2.xml file in the UDUNITS2_XML_PATH environment variable, although the default location is usually correct. For example, export UDUNITS2_XML_PATH=/home/user/anaconda3/share/udunits/udunits2.xml.

If you get an error that looks like assert(0 == _ut_unmap_symbol_to_unit(_ut_system, _c_char_p(b'Sv'), _UT_ASCII)) then setting the UDUNITS2_XML_PATH environment variable is the likely solution.

UDUNITS is available via conda with:

$ conda install -c conda-forge udunits2>=2.2.25

Alternatively, you can download and install UDUNITS directly from its source distribution following the documentation outlined on the unidata website

Environment variable configuration

You will need to add an environment variable to your system called ECCODES_DEFINITION_PATH that points to the definitions folder inside ecCodes. Once ecCodes is installed on your system, you can find this directory using the command:

find . -samefile */share/eccodes/definitions

If you encounter a warning from ecmwflibs about ignoring your specified environment variable, instead use the variable name ECMWFLIBS_ECCODES_DEFINITION_PATH

Transform FM15 files from the command line

#   basic cli command to transform TAC file of metar(s) and print resulting geojson records
#   both month and year as int values
transform-file example_metars.txt month year

Releasing

#   uploading to PyPI
#   make sure to update version number in pyproject.toml using vim or another IDE
rm -fr build dist *.egg-info
python3 -m build
twine upload dist/*

Contact

• Alex Thompson