Developing GribMagic

The workbench
1

Hi there,

we would like to write some notes about the GribMagic program, which received some love just recently and finally got published to PyPI a few days ago, see gribmagic · PyPI.

About

Originally conceived by Daniel Lassahn of alitiq (formerly meteoIntelligence), the GribMagic Python package was conceived as a bulk downloader for NWP data from different providers.

The original code has been refactored to be made available as a standalone package and some additional functionality has been added, which is described in the next section.

New features

General

All functionality has been made available from the command line.

DWD Downloader

The package gained an additional feature for downloading NWP data from DWD’s products COSMO and ICON, based on improvements to the canonical dwd-grib-downloader [1].

Regridding tool

Because ICON-GLOBAL data is only published using an triangular/icosahedral grid, a regridding program similar to DWD’s regrid has been added, in order to transform the data into a regular latitude-longiture/geographical grid.

bbox tool

Further, a bbox tool was added, in order to extract an area of interest from GRIB files using a bounding box or country code.

Setup

pip install gribmagic

Usage

Pointers to the documentation of the four main subsystems are:

Outlook

We would like to encourage all people interested in this program to participate by sharing their ideas and use-cases. We are looking for any kind of motivating feedback about any bugs or improvements which could be implemented. Contributing features by sending patches would be even sweeter.

  1. The corresponding upstream program is DeutscherWetterdienst/downloader, however @mhaberler’s fork with baseline improvements at was derived from the derivate docker-dwd-open-data-downloader. ↩︎

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More useful details

In order to understand more about the inner workings of the two main workhorse subsystems, GribMagic Unity vs. DWD GRIB Downloader, it makes sense to look at GribMagic Unity’s gribmagic/unity/knowledge folder vs. DWD GRIB Downloader’s models.json file in the code repository.

You will see that both subsystems strive for generality, but look at it from a different angle. Currently, GribMagic Unity can access more data sources from different providers. On the other hand, DWD GRIB Downloader makes it easier to slice specific parameters out of DWD’s ICON data, based on recipe description files as outlined at examples/dwd.