nuwe-pyeccodes

A python binding for ecCodes for python in Windows.

ecCodes by ECMWF has its own python binding which only supports python 2 and s not available on Windows. The new eccodes-python package on conda-forge can be used in python 3 and windows, and also supports JPEG packing. But it seems to has some problem currently. So, please try to use the official python binding first, and turn to this project if it is not working.

nuwe-pyeccodes provides some simple methods to process GRIB2 data based on ecCodes and supports python 3 (python 2 is not supported currently).

Requirments

ecCodes

Install ecCodes using CMake in Linux or Visual Studio on Windows.

It is recommended to build under anaconda on Windows (Enable USE_ECCODES_CONDA option for CMake).

pybind11 and python

Choose a python distribution (official Python or Anaconda Python) and install pybind11 package.

Building

Use CMake to build from source code.

Add pybind11 and ecCodes cmake module path to CMAKE_PREFIX_PATH.

If you aren't using anaconda on Windows, some Cmake variables are availabel to help find required libraries.

• OPENJP_INSTALL_PREFIX: OpenJPEG install prefix.
• EcCodes_INCLUDE_DIR: ecCodes include directory.
• EcCodes_LIBRARY_DIR: ecCodes library directory.

Getting Started

nuwe-pyeccodes supports two kind of APIs: handler classes and ecCodes functions.

Handler Classes

import nuwe_pyeccodes

grib_file_handler = nuwe_pyeccodes.GribFileHandler()
# open a grib file
grib_file_handler.openFile("grib_file_path")
while True:
    # load a message in grib file.
    grib_message_handler = grib_file_handler.next()
    if grib_message_handler is None:
        break

    # get string, long or double key value
    print(grib_message_handler.getString("shortName"))
    print(grib_message_handler.getLong("Ni"))
    print(grib_message_handler.getDouble("level"))

    # values is Numpy array.
    values = grib_message_handler.getDoubleArray("values")
    print(values[0])

grib_file_handler.closeFile()

ecCodes Functions

Some eccodes-python functions is supported. Such as:

• codes_grib_new_from_file
• codes_release
• codes_get
• codes_get_long
• codes_get_double
• codes_get_string
• codes_get_size
• codes_get_length
• codes_get_double_array

The API is the same as eccodes, so just one import line needs to be changed.

From

from eccodes import *

To

from nuwe_pyeccodes import *

Example

C++ Examples are in example directory.

License

Copyright © 2018-2019, Periilla Roc

nuwe-pyeccodes is licensed under The MIT License.