Dec 29, 2014 - Python module for reading and writing GRIB (editions 1 and 2) files. A grib message object displays summary info 3:Maximum temperature:K.

Python module for reading and writing GRIB (editions 1 and 2) files. GRIB is the World Meterological Organization standard for distributing gridded data. The module is a python interface to the GRIB API C library from the European Centre for Medium-Range Weather Forecasts (ECMWF).

• Python 2.4 or higher.
• numpy N-dimensional array object for python. Version 1.2.1 or higher (version 1.5.1 required for Python 3).
• pyproj Python interface to PROJ.4 library for cartographic transformations ormatplotlib and the basemap toolkit. Pyproj 1.8.9 is required for Python 3.
• GRIB API C library for encoding and decoding GRIB messages (edition 1 and edition 2). Version 1.8.0 or higher required. To be fully functional, the GRIB API library requires Jasper or OpenJPEG for JPEG200 encoding, and PNG for PNG encoding.

These dependencies are available via the package management system of most Linux distributions, and on MacOS X using macports. If you build grib_api yourself as a static library on a 64-bit system you may need to set CFLAGS to '-O2 -fPIC' before running the configure script. To use pygrib on Windows, you must use the Cygwin environment, since the grib_api library requires a posix environment. Cygwin installation instructions are available here.

• Download the source code.
• pygrib installation options can either be set with environment variables, or specified in a text file (setup.cfg). To use environment variables, set $GRIBAPI_DIR, $JASPER_DIR, $OPENJPEG_DIR, $PNG_DIR and $ZLIB_DIR so that the include files and libraries for GRIB API, Jasper, OpenJPEG, PNG and zlib will be found. For example, the include files for jasper should be found in $JASPER_DIR/include or $JASPER_DIR/include/jasper, and the jasper library should be found in $JASPER_DIR/lib or $JASPER_DIR/lib64. If any of those environment variables are not set, then it is assumed that GRIB API was not built with support for that library. If the libraries and include files are installed in separate locations, the environment variables $GRIBAPI_INCDIR and $GRIBAPI_LIBDIR can be used to define the locations separately (same goes for JASPER, OPENJPEG, PNG and ZLIB). Note that if both $GRIBAPI_DIR and $GRIBAPI_INCDIR/$GRIBAPI_LIBDIR are specified, $GRIBAPI_DIR takes precedence. To use setup.cfg, copy setup.cfg.template to setup.cfg, open setup.cfg in a text editor and follow the instructions in the comments for editing.
• Run 'python setup.py build' and then 'python setup.py install', as root if necessary. Note that if you are using environment variables to specify the build options, you cannot build and install in one step with 'sudo python setup.py install', since sudo does not pass environment variables. Instead, run 'python setup.py build' first as a regular user, then run 'sudo python setup.py install' if the install directory requires admin or root privileges.
• Run 'python test.py' to test your installation.
• Look at examples in test directory (most require matplotlib and basemap).
• If you're on MacOS X, see README.macosx for special instruction on how to install pygrib and all it's dependencies using macports.

• from the python interpreter prompt, import the package:
• open a GRIB file, create a grib message iterator:
• pygrib open instances behave like regular python file objects, with seek, tell, read, readline and close methods, except that offsets are measured in grib messages instead of bytes:
• print an inventory of the file:
• find the first grib message with a matching name:
• extract the data values using the 'values' key (grb.keys() will return a list of the available keys):
• get the latitudes and longitudes of the grid:
• get the second grib message:
• extract data and get lat/lon values for a subset over North America:
• modify the values associated with existing keys (either via attribute or dictionary access):
• get the binary string associated with the coded message:
• write the modified message to a new GRIB file:

• see below for the full python API documentation.

Author: Jeffrey Whitaker.

Contact:Jeff Whitaker

Version: 2.0.0

Copyright: copyright 2010 by Jeffrey Whitaker.

License: Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.